Issue: Generic type 'Observer' requires 1 type argument(s).

Observer types in Firebase 5.0.0 not fixed on all positions. In commit #770 the interface Observer is now "export interface Observer {...}", but in "/packages/auth-types/index.d.ts" at line 271 and 276 it's still the old one. The same at "/packages/storage-types/index.d.ts" line 80.

Environment

• Operating System version: Windows 10
• Firebase SDK version: 5.0.0