fix(material/expansion): Focus remains on the header when clicked on next or cancel button inside the panel.

When we click on next or cancel button the focus remained on the current panel header. This fix uses focus method from the class and changes the `FocusMonitor` to be in `EVENTUAL`

Fixes #22942

Author: mistrykaran91

src/material/expansion/expansion-panel-header.ts

@@ -6,7 +6,13 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import {FocusableOption, FocusMonitor, FocusOrigin} from '@angular/cdk/a11y';
+import {
+  FOCUS_MONITOR_DEFAULT_OPTIONS,
+  FocusableOption,
+  FocusMonitor,
+  FocusMonitorDetectionMode,
+  FocusOrigin,
+} from '@angular/cdk/a11y';
 import {ENTER, hasModifierKey, SPACE} from '@angular/cdk/keycodes';
 import {
   AfterViewInit,
@@ -57,6 +63,15 @@ import {_StructuralStylesLoader} from '../core';
     '(click)': '_toggle()',
     '(keydown)': '_keydown($event)',
   },
+  providers: [
+    FocusMonitor,
+    {
+      provide: FOCUS_MONITOR_DEFAULT_OPTIONS,
+      useValue: {
+        detectionMode: FocusMonitorDetectionMode.EVENTUAL,
+      },
+    },
+  ],
 })
 export class MatExpansionPanelHeader implements AfterViewInit, OnDestroy, FocusableOption {
   panel = inject(MatExpansionPanel, {host: true});
@@ -98,9 +113,7 @@ export class MatExpansionPanelHeader implements AfterViewInit, OnDestroy, Focusa
     ).subscribe(() => this._changeDetectorRef.markForCheck());
 
     // Avoids focus being lost if the panel contained the focused element and was closed.
-    panel.closed
-      .pipe(filter(() => panel._containsFocus()))
-      .subscribe(() => this._focusMonitor.focusVia(this._element, 'program'));
+    panel.closed.pipe(filter(() => panel._containsFocus())).subscribe(() => this.focus());
 
     if (defaultOptions) {
       this.expandedHeight = defaultOptions.expandedHeight;