bug(mat-menu): VoiceOver user on mobile is able to navigate out of an opened Menu

### Description

On iOS, with VoiceOver turned on, after a user opens a menu and they start swiping through the menu items in order to move focus from one item to the next, when they reach the first or last menu item and swipe respectively backward or forward, VoiceOver focus is moved outside of the menu into the next element

### Reproduction

StackBlitz link: https://material.angular.dev/components/menu/overview#menu-overview
Steps to reproduce:
1. On an iOS device, turn VoiceOver on
2. Navigate to the menu example
3. Open the menu
4. Swipe forward until VoiceOver focus leaves the menu

### Expected Behavior

Focus is trapped in the menu

### Actual Behavior

VoiceOver focus moves outside of the menu

### Environment

- Angular: v21
- CDK/Material: v21
- Browser(s): Any
- Operating System (e.g. Windows, macOS, Ubuntu): iOS with VoiceOver turned on

Start by reproducing the issue in the linked Material menu overview on an iOS device with VoiceOver enabled, then trace the mat-menu focus handling at the first and last menu items. Done means forward and backward swipes keep VoiceOver focus inside the opened menu rather than moving to the next element.

Written by the indexing model from the issue text.