feat(angular): add custom injector support for modal and popover controllers (#30899)

Issue number: resolves #30638

---------

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## What is the current behavior?
When using `ModalController.create()` or `PopoverController.create()` in
Angular, components rendered inside overlays cannot access non-global
services or tokens from the component tree. For example, route-scoped
services or Angular's Dir directive for bidirectional text support are
not accessible from within a modal, requiring complex workarounds with
wrapper components.

## What is the new behavior?
`ModalController.create()` and `PopoverController.create()` now accept
an optional injector property that allows passing a custom Angular
Injector. This enables overlay components to access services and tokens
that are not available in the root injector, such as route-scoped
services or the Dir directive from Angular CDK.

```typescript
const customInjector = Injector.create({
  providers: [{ provide: MyService, useValue: myServiceInstance }],
  parent: this.injector,
});
```

```typescript
const modal = await this.modalController.create({
  component: MyModalComponent,
  injector: customInjector,
});
```

## Does this introduce a breaking change?

- [ ] Yes
- [X] No

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## Other information

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screenshots of how the component looks before and after the change. -->

Current dev build:
```
8.7.17-dev.11769628168.11eca7cd
```