fix: panic in ListingTableFactory when session is not SessionState (#20139)

## Which issue does this PR close?

- Closes #20113.

## Rationale for this change

This PR fixes a potential panic in `ListingTableFactory::create` when
the provided
[Session](cci:2://file:///Users/evangelisilva/.gemini/antigravity/scratch/datafusion/datafusion/session/src/session.rs:71:0-140:1)
instance is not a `SessionState`.

Previously, the code used `.unwrap()` on
`downcast_ref::<SessionState>()`. If a custom
[Session](cci:2://file:///Users/evangelisilva/.gemini/antigravity/scratch/datafusion/datafusion/session/src/session.rs:71:0-140:1)
implementation was used (which is allowed by the trait), this would
cause a crash. This change replaces `.unwrap()` with `ok_or_else`,
returning a proper `DataFusionError::Internal` instead.

## What changes are included in this PR?

- Replaced `.unwrap()` with `ok_or_else` in
`ListingTableFactory::create` to safely handle session downcasting.
- Added a regression test
[test_create_with_invalid_session](cci:1://file:///Users/evangelisilva/.gemini/antigravity/scratch/datafusion/datafusion/core/src/datasource/listing_table_factory.rs:554:4-638:5)
in
[datafusion/core/src/datasource/listing_table_factory.rs](cci:7://file:///Users/evangelisilva/.gemini/antigravity/scratch/datafusion/datafusion/core/src/datasource/listing_table_factory.rs:0:0-0:0)
that uses a
[MockSession](cci:2://file:///Users/evangelisilva/.gemini/antigravity/scratch/datafusion/datafusion/core/src/datasource/listing_table_factory.rs:570:8-570:27)
to verify the error is returned instead of panicking.

## Are these changes tested?

Yes.
- Added new unit test
[test_create_with_invalid_session](cci:1://file:///Users/evangelisilva/.gemini/antigravity/scratch/datafusion/datafusion/core/src/datasource/listing_table_factory.rs:554:4-638:5).
- Ran `cargo test -p datafusion --lib
datasource::listing_table_factory::tests::test_create_with_invalid_session`
and it passed.

## Are there any user-facing changes?

No.

---------

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

Author: evangelisilva

datafusion/core/src/datasource/listing_table_factory.rs

@@ -54,7 +54,15 @@ impl TableProviderFactory for ListingTableFactory {
         cmd: &CreateExternalTable,
     ) -> Result<Arc<dyn TableProvider>> {
         // TODO (https://github.com/apache/datafusion/issues/11600) remove downcast_ref from here. Should file format factory be an extension to session state?
-        let session_state = state.as_any().downcast_ref::<SessionState>().unwrap();
+        let session_state =
+            state
+                .as_any()
+                .downcast_ref::<SessionState>()
+                .ok_or_else(|| {
+                    datafusion_common::internal_datafusion_err!(
+                        "ListingTableFactory requires SessionState"
+                    )
+                })?;
         let file_format = session_state
             .get_file_format_factory(cmd.file_type.as_str())
             .ok_or(config_datafusion_err!(
@@ -546,4 +554,103 @@ mod tests {
             "Statistics cache should not be pre-warmed when collect_statistics is disabled"
         );
     }
+
+    #[tokio::test]
+    async fn test_create_with_invalid_session() {
+        use async_trait::async_trait;
+        use datafusion_catalog::Session;
+        use datafusion_common::Result;
+        use datafusion_common::config::TableOptions;
+        use datafusion_execution::TaskContext;
+        use datafusion_execution::config::SessionConfig;
+        use datafusion_physical_expr::PhysicalExpr;
+        use datafusion_physical_plan::ExecutionPlan;
+        use std::any::Any;
+        use std::collections::HashMap;
+        use std::sync::Arc;
+
+        // A mock Session that is NOT SessionState
+        #[derive(Debug)]
+        struct MockSession;
+
+        #[async_trait]
+        impl Session for MockSession {
+            fn session_id(&self) -> &str {
+                "mock_session"
+            }
+            fn config(&self) -> &SessionConfig {
+                unimplemented!()
+            }
+            async fn create_physical_plan(
+                &self,
+                _logical_plan: &datafusion_expr::LogicalPlan,
+            ) -> Result<Arc<dyn ExecutionPlan>> {
+                unimplemented!()
+            }
+            fn create_physical_expr(
+                &self,
+                _expr: datafusion_expr::Expr,
+                _df_schema: &DFSchema,
+            ) -> Result<Arc<dyn PhysicalExpr>> {
+                unimplemented!()
+            }
+            fn scalar_functions(
+                &self,
+            ) -> &HashMap<String, Arc<datafusion_expr::ScalarUDF>> {
+                unimplemented!()
+            }
+            fn aggregate_functions(
+                &self,
+            ) -> &HashMap<String, Arc<datafusion_expr::AggregateUDF>> {
+                unimplemented!()
+            }
+            fn window_functions(
+                &self,
+            ) -> &HashMap<String, Arc<datafusion_expr::WindowUDF>> {
+                unimplemented!()
+            }
+            fn runtime_env(&self) -> &Arc<datafusion_execution::runtime_env::RuntimeEnv> {
+                unimplemented!()
+            }
+            fn execution_props(
+                &self,
+            ) -> &datafusion_expr::execution_props::ExecutionProps {
+                unimplemented!()
+            }
+            fn as_any(&self) -> &dyn Any {
+                self
+            }
+            fn table_options(&self) -> &TableOptions {
+                unimplemented!()
+            }
+            fn table_options_mut(&mut self) -> &mut TableOptions {
+                unimplemented!()
+            }
+            fn task_ctx(&self) -> Arc<TaskContext> {
+                unimplemented!()
+            }
+        }
+
+        let factory = ListingTableFactory::new();
+        let mock_session = MockSession;
+
+        let name = TableReference::bare("foo");
+        let cmd = CreateExternalTable::builder(
+            name,
+            "foo.csv".to_string(),
+            "csv",
+            Arc::new(DFSchema::empty()),
+        )
+        .build();
+
+        // This should return an error, not panic
+        let result = factory.create(&mock_session, &cmd).await;
+        assert!(result.is_err());
+        assert!(
+            result
+                .unwrap_err()
+                .strip_backtrace()
+                .contains("Internal error: ListingTableFactory requires SessionState")
+        );
+    }
 }