Fix null safety error in fuchsia_tester.dart (#112414)
Fix null safety error in fuchsia_tester.dart (#112414)


flutter/flutter,tvolkert/flutter,tvolkert/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter