fix(router): do not finish bootstrap until all the routes are resolved (#14608)

Fixes #12162
closes #14155

tools/public_api_guard/common/index.d.ts

@@ -86,6 +86,9 @@ export declare class Location {
     static stripTrailingSlash(url: string): string;
 }
 
+/** @experimental */
+export declare const LOCATION_INITIALIZED: InjectionToken<Promise<any>>;
+
 /** @experimental */
 export interface LocationChangeEvent {
     type: string;