fix(): FirebaseApp Class should not implement app.App (#2060)

While giving us a bit more type safety in development, implementing
app.App allows the Firebase JS SDK to break our builds in minor
releases. Which has bit us more than once.

I do not believe this is worth keeping around any longer.

Fixes #2059

Author: jamesdaniels

package.json

@@ -46,9 +46,9 @@
     "utf-8-validate": "~4.0.0"
   },
   "devDependencies": {
+    "@angular/animations": ">=6.0.0 <8",
     "@angular/compiler-cli": ">=6.0.0 <8",
     "@angular/platform-server": ">=6.0.0 <8",
-    "@angular/animations": ">=6.0.0 <8",
     "@types/jasmine": "^2.5.36",
     "@types/request": "0.0.30",
     "concurrently": "^2.2.0",

src/core/firebase.app.module.ts

@@ -1,5 +1,5 @@
 import { InjectionToken, NgModule, Optional } from '@angular/core';
-import { app, auth, database, firestore, functions, messaging, storage } from 'firebase/app';
+import { auth, database, firestore, functions, messaging, storage } from 'firebase/app';
 // @ts-ignore (https://github.com/firebase/firebase-js-sdk/pull/1206)
 import firebase from 'firebase/app'; // once fixed can pull in as "default as firebase" above
 
@@ -19,14 +19,11 @@ export type FirebaseFunctions = functions.Functions;
 
 // Have to implement as we need to return a class from the provider, we should consider exporting
 // this in the firebase/app types as this is our highest risk of breaks
-export class FirebaseApp implements app.App {
+export class FirebaseApp {
     name: string;
     options: {};
     auth: () => FirebaseAuth;
-    // app.App database() doesn't take a databaseURL arg in the public types?
     database: (databaseURL?: string) => FirebaseDatabase;
-    // automaticDataCollectionEnabled is now private? _automaticDataCollectionEnabled?
-    // automaticDataCollectionEnabled: true,
     messaging: () => FirebaseMessaging;
     storage: (storageBucket?: string) => FirebaseStorage;
     delete: () => Promise<void>;