refactor(core): replace non output EventEmitter with Subject. (angular#54666)

Semantcly we're shifting away from using `EventEmitter` on non-outputs. PR Close angular#54666

Author: JeanMeche

packages/core/src/linker/query_list.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Observable} from 'rxjs';
+import {Observable, Subject} from 'rxjs';
 
 import {EventEmitter} from '../event_emitter';
 import {Writable} from '../interface/type';
@@ -48,7 +48,7 @@ export class QueryList<T> implements Iterable<T> {
  private _onDirty?: () => void = undefined;
  private _results: Array<T> = [];
  private _changesDetected: boolean = false;
- private _changes: EventEmitter<QueryList<T>> | undefined = undefined;
+ private _changes: Subject<QueryList<T>> | undefined = undefined;
 
  readonly length: number = 0;
  readonly first: T = undefined!;
@@ -58,7 +58,7 @@ export class QueryList<T> implements Iterable<T> {
  * Returns `Observable` of `QueryList` notifying the subscriber of changes.
  */
  get changes(): Observable<any> {
- return (this._changes ??= new EventEmitter());
+ return (this._changes ??= new Subject());
  }
 
  /**
@@ -171,7 +171,7 @@ export class QueryList<T> implements Iterable<T> {
  */
  notifyOnChanges(): void {
  if (this._changes !== undefined && (this._changesDetected || !this._emitDistinctChangesOnly))
- this._changes.emit(this);
+ this._changes.next(this);
  }
 
  /** @internal */