[ci] Switch to macOS VM with Flutter pre-installed (#1313)
[ci] Switch to macOS VM with Flutter pre-installed (#1313)

[ci] Switch to macOS VM with Flutter pre-installed
googleads/googleads-mobile-flutter,firebase/flutterfire,firebase/flutterfire,googleads/googleads-mobile-flutter,firebase/flutterfire,firebase/flutterfire,firebase/flutterfire,googleads/googleads-mobile-flutter,firebase/flutterfire,firebase/flutterfire,googleads/googleads-mobile-flutter,firebase/flutterfire,firebase/flutterfire,firebase/flutterfire