feat(core): Drop public factories property for IterableDiffers : Breaking change (#49598)

The `factories` property was marked as deprecated in v4 to make it private. Let's move it to private.

PR Close #49598

Author: JeanMeche

goldens/public-api/core/index.md

@@ -880,8 +880,6 @@ export class IterableDiffers {
     // (undocumented)
     static create(factories: IterableDifferFactory[], parent?: IterableDiffers): IterableDiffers;
     static extend(factories: IterableDifferFactory[]): StaticProvider;
-    // @deprecated (undocumented)
-    factories: IterableDifferFactory[];
     // (undocumented)
     find(iterable: any): IterableDifferFactory;
     // (undocumented)

packages/core/src/change_detection/differs/iterable_differs.ts

@@ -195,13 +195,7 @@ export class IterableDiffers {
   static ɵprov = /** @pureOrBreakMyCode */ ɵɵdefineInjectable(
       {token: IterableDiffers, providedIn: 'root', factory: defaultIterableDiffersFactory});
 
-  /**
-   * @deprecated v4.0.0 - Should be private
-   */
-  factories: IterableDifferFactory[];
-  constructor(factories: IterableDifferFactory[]) {
-    this.factories = factories;
-  }
+  constructor(private factories: IterableDifferFactory[]) {}
 
   static create(factories: IterableDifferFactory[], parent?: IterableDiffers): IterableDiffers {
     if (parent != null) {

packages/core/test/change_detection/differs/iterable_differs_spec.ts

@@ -44,6 +44,7 @@ import {TestBed} from '@angular/core/testing';
       const parent = IterableDiffers.create(<any>[factory1]);
       const child = IterableDiffers.create(<any>[factory2], parent);
 
+      // @ts-expect-error private member
       expect(child.factories).toEqual([factory2, factory1]);
     });
 
@@ -55,7 +56,10 @@ import {TestBed} from '@angular/core/testing';
         const childInjector =
             Injector.create({providers: [IterableDiffers.extend([factory2])], parent: injector});
 
+        // @ts-expect-error factories is a private member
         expect(injector.get<IterableDiffers>(IterableDiffers).factories).toEqual([factory1]);
+
+        // @ts-expect-error factories is a private member
         expect(childInjector.get<IterableDiffers>(IterableDiffers).factories).toEqual([
           factory2, factory1
         ]);