fix: import shell execution test type

Agent-Logs-Url: https://github.com/microsoft/vscode-python-environments/sessions/5f628821-9c7b-48a6-9f5f-9fccb9a33bf6

Co-authored-by: eleanorjboyd <26030610+eleanorjboyd@users.noreply.github.com>

Author: Copilot

src/test/features/execution/runAsTask.unit.test.ts

@@ -1,6 +1,6 @@
 import * as assert from 'assert';
 import * as sinon from 'sinon';
-import { Task, TaskExecution, TaskPanelKind, TaskRevealKind, TaskScope, Uri, WorkspaceFolder } from 'vscode';
+import { ShellExecution, Task, TaskExecution, TaskPanelKind, TaskRevealKind, TaskScope, Uri, WorkspaceFolder } from 'vscode';
 import { PythonEnvironment, PythonTaskExecutionOptions } from '../../../api';
 import * as logging from '../../../common/logging';
 import * as tasksApi from '../../../common/tasks.apis';