feat(service-worker): allow configuring when the SW is registered (#21842)

Fixes #20970

PR Close #21842

tools/public_api_guard/service-worker/service-worker.d.ts

@@ -21,6 +21,7 @@ export declare class SwPush {
 
 export declare abstract class SwRegistrationOptions {
     enabled?: boolean;
+    registrationStrategy?: (() => Observable<any>) | string;
     scope?: string;
 }