Memory Leak in Injector

I've encountered a possible memory leak while using `OverlayRef` and `Injector`.

#### Reproduction

Inside `AppComponent` there is a click event on a button. That click event will generate an array and pass that array to another component using `ComponentPortal`

The constructor and the click event from `AppComponent`:

```
// ? AppComponent constructor
constructor(private overlay: Overlay) {
this.#overlayRef = this.overlay.create({
positionStrategy: this.overlay
.position()
.global()
.centerHorizontally()
.centerVertically(),
hasBackdrop: true,
});

this.#overlayRef.backdropClick().subscribe(() => this.#overlayRef.detach());
}

onClick(){
const output = new Array(1000).fill('asfasdf');
this.#overlayRef.attach(
new ComponentPortal(
MyComponent,
null,
Injector.create({
providers: [{ provide: MY_TOKEN, useValue: output }],
})
)
);
}
```

#### Actual Behavior

It looks like each time the modal is created the data generated and injected in the component, but once the modal disappears, the data is not removed from the memory.


#### Environment

- Angular:
- "@angular/core": "~11.2.5",

- CDK/Material:
- "@angular/cdk": "^11.2.4",
- Browser(s): Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): Windows10

El informe menciona AppComponent, MyComponent, OverlayRef, Injector y ComponentPortal; empieza reproduciendo clics repetidos y comprobando los heap snapshots. Rastrea el ciclo de vida de attach/detach del overlay y las referencias de Injector.create; después, confirma si el array inyectado se libera tras el cierre y documenta el resultado en una prueba de regresión o en un diagnóstico documentado.

Escrito por el modelo de indexación a partir del texto del issue.