6.12.0: Firebase.podspec FirebaseAuth pod version reverted, cherry-pick #4231 (#4234)

* Firebase.podspec - revert Auth

* check_whitespaces.sh: ignore notices. (#4231)

Firebase.podspec

@@ -60,7 +60,7 @@ Simplify your iOS development, grow your user base, and monetize more effectivel
 
   s.subspec 'Auth' do |ss|
     ss.dependency 'Firebase/CoreOnly'
-    ss.dependency 'FirebaseAuth', '~> 6.4.0'
+    ss.dependency 'FirebaseAuth', '~> 6.3.1'
   end
 
   s.subspec 'Database' do |ss|

scripts/check_whitespace.sh

@@ -29,6 +29,7 @@ git grep "${options[@]}" -- \
     ':(exclude)Firebase/CoreDiagnostics/FIRCDLibrary/Protogen/nanopb' \
     ':(exclude)Firebase/CoreDiagnostics/ProtoSupport' \
     ':(exclude)CoreOnly/NOTICES' \
+    ':(exclude)Firebase/Firebase/NOTICES' \
     ':(exclude)Firebase/InAppMessaging/ProtoSupport' \
     ':(exclude)Firebase/InAppMessaging/Analytics/Protogen/nanopb' \
     ':(exclude)Firestore/Protos/nanopb' \
@@ -36,7 +37,8 @@ git grep "${options[@]}" -- \
     ':(exclude)Firestore/Protos/objc' \
     ':(exclude)Firestore/third_party/abseil-cpp' \
     ':(exclude)GoogleDataTransportCCTSupport/GDTCCTLibrary/Protogen/nanopb' \
-    ':(exclude)GoogleDataTransportCCTSupport/ProtoSupport'
+    ':(exclude)GoogleDataTransportCCTSupport/ProtoSupport' \
+    ':(exclude)ZipBuilder/Template/NOTICES'
 
 if [[ $? == 0 ]]; then
   echo "ERROR: Trailing whitespace found in the files above. Please fix."