dataconnect(chore): use token objects instead of strings to improve type safety#8027

dconeybe merged 6 commits intomainfirebase/firebase-android-sdk:mainfrom

dconeybe/dataconnect/DataConnectGrpcMetadataTokenRefactorfirebase/firebase-android-sdk:dconeybe/dataconnect/DataConnectGrpcMetadataTokenRefactorCopy head branch name to clipboard