revert: drop component detection broadening in template-no-passed-in-event-handlers

Removes the PascalCase-OR-@-OR-this.-OR-dot heuristic and the associated
tests for <this.MyComponent>, <@someComponent>, <ns.Widget>, <my-button>,
<custom-el>. Reverts to master's PascalCase-only gate.

Better addressed by scope analysis once ember-eslint-parser exposes
richer HBS scope — revisit as a separate PR then.

Keeps the ignore-config format fix (argName without @) and the event
list alignment with upstream.

Author: johanrd

lib/rules/template-no-passed-in-event-handlers.js

@@ -77,19 +77,10 @@ module.exports = {
 
     return {
       GlimmerElementNode(node) {
-        // Only check component invocations. In GTS, dashed tags like <my-button>
-        // are HTML (imports can't have dashes); lowercase non-dashed tags are
-        // HTML. Components are PascalCase, @-prefixed args, this.-prefixed
-        // references, or dot-paths (re-exports).
-        const isComponent =
-          /^[A-Z]/.test(node.tag) ||
-          node.tag.startsWith('@') ||
-          node.tag.startsWith('this.') ||
-          node.tag.includes('.');
-        if (!isComponent) {
+        // Only check component invocations (PascalCase)
+        if (!/^[A-Z]/.test(node.tag)) {
           return;
         }
-
         // Skip built-in Input/Textarea
         if (node.tag === 'Input' || node.tag === 'Textarea') {
           return;

tests/lib/rules/template-no-passed-in-event-handlers.js

@@ -36,10 +36,6 @@ ruleTester.run('template-no-passed-in-event-handlers', rule, {
     '<template><Input @click={{this.handleClick}} /></template>',
     '<template><Textarea @click={{this.handleClick}} /></template>',
 
-    // HTML elements are not checked (in GTS <my-button> is HTML, not a component)
-    '<template><my-button @click={{this.handleClick}} /></template>',
-    '<template><custom-el @submit={{this.handleSubmit}} /></template>',
-
     // mouseMove/mouseEnter/mouseLeave are not Ember classic-event aliases
     '<template><Foo @mouseMove={{this.handleMove}} /></template>',
     '<template><Foo @mouseEnter={{this.handleEnter}} /></template>',
@@ -105,22 +101,6 @@ ruleTester.run('template-no-passed-in-event-handlers', rule, {
       output: null,
       errors: [{ messageId: 'unexpected' }],
     },
-    // Non-PascalCase component forms: this.-prefixed, @-prefixed, dot-path
-    {
-      code: '<template><this.MyComponent @click={{this.handleClick}} /></template>',
-      output: null,
-      errors: [{ messageId: 'unexpected' }],
-    },
-    {
-      code: '<template><@someComponent @click={{this.handleClick}} /></template>',
-      output: null,
-      errors: [{ messageId: 'unexpected' }],
-    },
-    {
-      code: '<template><ns.Widget @submit={{this.handleSubmit}} /></template>',
-      output: null,
-      errors: [{ messageId: 'unexpected' }],
-    },
     {
       code: '<template>{{foo click=this.handleClick}}</template>',
       output: null,