fix(material/schematics): update navigation schematic with modern Angular pat...

[Pavaneswar6699]

Problem

The navigation schematic generates code with several issues:

1. Material 2 → Material 3: Uses deprecated color="primary" attribute
2. Outdated patterns: Uses RxJS Observables instead of modern Angular Signals
3. Mobile UX bug: Sidenav doesn't close when clicking on navigation items

Solution

• Replaced color="primary" with mat-elevation-z4 class for Material 3
• Converted Observable isHandset$ to Signal isHandset for modern Angular (17+)
• Added (click)="drawer.close()" to nav links for better mobile UX
• Simplified template logic with direct signal calls instead of async pipe

Testing

• Generated navigation schematic and verified it works without errors
• Mobile sidenav now closes when clicking navigation items
• Template uses modern Angular patterns

Fixes #33381

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