fix(cdk/listbox): prevent form submission on click (#25858)

`CdkOption` can be placed on any element which means that it could cause a `form` to be submitted if it's placed on a `button`. These changes add a `preventDefault` to avoid the submission.

(cherry picked from commit ce4806a)

src/cdk/listbox/listbox.spec.ts

@@ -2,7 +2,7 @@ import {fakeAsync, TestBed, tick} from '@angular/core/testing';
 import {Component, Type} from '@angular/core';
 import {By} from '@angular/platform-browser';
 import {CdkListbox, CdkListboxModule, CdkOption, ListboxValueChangeEvent} from './index';
-import {dispatchKeyboardEvent, dispatchMouseEvent} from '../testing/private';
+import {dispatchFakeEvent, dispatchKeyboardEvent, dispatchMouseEvent} from '../testing/private';
 import {
   A,
   B,
@@ -139,6 +139,14 @@ describe('CdkOption and CdkListbox', () => {
       expect(fixture.componentInstance.changedOption?.id).toBe(options[0].id);
     });
 
+    it('should prevent the default click action', () => {
+      const {fixture, optionEls} = setupComponent(ListboxWithOptions);
+      const event = dispatchFakeEvent(optionEls[1], 'click');
+      fixture.detectChanges();
+
+      expect(event.defaultPrevented).toBe(true);
+    });
+
     it('should select and deselect range on option SHIFT + click', () => {
       const {testComponent, fixture, listbox, optionEls} = setupComponent(ListboxWithOptions);
       testComponent.isMultiselectable = true;

src/cdk/listbox/listbox.ts

@@ -873,6 +873,7 @@ export class CdkListbox<T = unknown> implements AfterContentInit, OnDestroy, Con
    * @param option The option that was clicked.
    */
   private _handleOptionClicked(option: CdkOption<T>, event: MouseEvent) {
+    event.preventDefault();
     this.listKeyManager.setActiveItem(option);
     if (event.shiftKey && this.multiple) {
       this.triggerRange(