app.module.ts: attempt to modify registrationStrategy to registerImmediately

refs #588

src/app/app.module.ts

@@ -196,7 +196,7 @@ const appRoutes: Routes = [
           enabled: environment.production,
           // Register the ServiceWorker as soon as the application is stable
           // or after 30 seconds (whichever comes first).
-          registrationStrategy: 'registerWhenStable:30000'
+          registrationStrategy: 'registerImmediately'
         })
     ],
     declarations: [