Fix migration bugs #791

Job	Run time
spm-build-test (macos-latest, macosx)	1m 45s
pod-lib-lint (macos-13, GoogleSignIn.podspec)	10m 6s
spm-build-test (macos-latest, iphonesimulator)	2m 19s
pod-lib-lint (macos-13, GoogleSignIn.podspec, --use-static-frameworks)	33m 24s
pod-lib-lint (macos-13, GoogleSignInSwiftSupport.podspec, --use-static-frameworks)	11m 4s
pod-lib-lint (macos-13, GoogleSignInSwiftSupport.podspec)	8m 50s
	1h 7m 28s

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