refactor: avoid clearing too much content in deferred content

The deferred content directive currently calls `ViewContainerRef.clear` which may end up removing content that the directive doesn't actually own. These changes adjust the directive so it only removes the view it inserted itself.

(cherry picked from commit ef6ffb4)

Author: crisbeto

src/aria/deferred-content/deferred-content.ts

@@ -14,6 +14,8 @@ import {
   signal,
   ViewContainerRef,
   model,
+  EmbeddedViewRef,
+  OnDestroy,
 } from '@angular/core';
 
 /**
@@ -41,25 +43,40 @@ export class DeferredContentAware {
  * ```
  */
 @Directive()
-export class DeferredContent {
+export class DeferredContent implements OnDestroy {
   private readonly _deferredContentAware = inject(DeferredContentAware, {optional: true});
   private readonly _templateRef = inject(TemplateRef);
   private readonly _viewContainerRef = inject(ViewContainerRef);
+  private _currentViewRef: EmbeddedViewRef<unknown> | null = null;
   private _isRendered = false;
 
   readonly deferredContentAware = signal(this._deferredContentAware);
 
   constructor() {
     afterRenderEffect(() => {
       if (this.deferredContentAware()?.contentVisible()) {
-        if (this._isRendered) return;
-        this._viewContainerRef.clear();
-        this._viewContainerRef.createEmbeddedView(this._templateRef);
-        this._isRendered = true;
+        if (!this._isRendered) {
+          this._destroyContent();
+          this._currentViewRef = this._viewContainerRef.createEmbeddedView(this._templateRef);
+          this._isRendered = true;
+        }
       } else if (!this.deferredContentAware()?.preserveContent()) {
-        this._viewContainerRef.clear();
+        this._destroyContent();
         this._isRendered = false;
       }
     });
   }
+
+  ngOnDestroy(): void {
+    this._destroyContent();
+  }
+
+  private _destroyContent() {
+    const ref = this._currentViewRef;
+
+    if (ref && !ref.destroyed) {
+      ref.destroy();
+      this._currentViewRef = null;
+    }
+  }
 }