Revert "refactor(core): tree-shake application_module providers (#23477)"

This reverts commit eb031c6ff1.

The change is breaking targets in g3 see cl/194336387.

packages/platform-server/src/styles_host.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Inject, Injectable, Optional} from '@angular/core';
+import {ApplicationRef, Inject, Injectable, Optional} from '@angular/core';
 import {DOCUMENT, ɵDomAdapter as DomAdapter, ɵSharedStylesHost as SharedStylesHost, ɵTRANSITION_ID, ɵgetDOM as getDOM} from '@angular/platform-browser';
 
 @Injectable()