Remove unnecessary dependencies on Firebase umbrella podspec (#968)

Author: paulb777

FirebaseAuthUI.podspec

@@ -17,8 +17,7 @@ Pod::Spec.new do |s|
 
   s.public_header_files = 'FirebaseAuthUI/Sources/Public/FirebaseAuthUI/*.h'
   s.source_files = 'FirebaseAuthUI/Sources/**/*.{h,m}'
-  s.dependency 'Firebase/Auth', '~> 8.0'
-  s.dependency 'FirebaseAuth'
+  s.dependency 'FirebaseAuth', '~> 8.0'
   s.dependency 'FirebaseCore'
   s.dependency 'GoogleUtilities/UserDefaults'
   s.resource_bundles = {

FirebaseDatabaseUI.podspec

@@ -17,6 +17,6 @@ Pod::Spec.new do |s|
 
   s.public_header_files = 'FirebaseDatabaseUI/Sources/Public/FirebaseDatabaseUI/*.h'
   s.source_files = 'FirebaseDatabaseUI/Sources/**/*.{h,m}'
-  s.dependency 'Firebase/Database', '~> 8.0'
+  s.dependency 'FirebaseDatabase', '~> 8.0'
 
 end

FirebaseFirestoreUI.podspec

@@ -17,7 +17,6 @@ Pod::Spec.new do |s|
 
   s.public_header_files = 'FirebaseFirestoreUI/Sources/Public/FirebaseFirestoreUI/*.h'
   s.source_files = 'FirebaseFirestoreUI/Sources/**/*.{h,m}'
-  s.dependency 'Firebase/Firestore'
   s.dependency 'FirebaseFirestore', '~> 8.0'
 
 end

FirebaseStorageUI.podspec

@@ -19,8 +19,7 @@ Pod::Spec.new do |s|
   s.tvos.deployment_target = '11.0'
   s.public_header_files = 'FirebaseStorageUI/Sources/Public/FirebaseStorageUI/*.h'
   s.source_files = 'FirebaseStorageUI/Sources/**/*.{h,m}'
-  s.dependency 'Firebase/Storage', '~> 8.0'
-  s.dependency 'FirebaseStorage'
+  s.dependency 'FirebaseStorage', '~> 8.0'
   s.dependency 'GTMSessionFetcher/Core', '~> 1.5.0'
   s.dependency 'SDWebImage', '~> 5.6'