Remove unused source file (#5639)

FirebaseRemoteConfig.podspec

@@ -28,7 +28,6 @@ app update.
 
   base_dir = "FirebaseRemoteConfig/Sources/"
   s.source_files = base_dir + '**/*.[mh]'
-  s.requires_arc = base_dir + '*.m'
   s.public_header_files = base_dir + 'Public/*.h'
   s.private_header_files = base_dir + 'Private/*.h'
   s.pod_target_xcconfig = {
@@ -44,7 +43,6 @@ app update.
   s.dependency 'FirebaseInstallations', '~> 1.1'
   s.dependency 'GoogleUtilities/Environment', '~> 6.2'
   s.dependency 'GoogleUtilities/NSData+zlib', '~> 6.2'
-  s.dependency 'Protobuf', '~> 3.9', '>= 3.9.2'
 
   s.test_spec 'unit' do |unit_tests|
     # TODO(dmandar) - Update or delete the commented files.