Reenabled the linter. Bug: https://github.com/flutter/flutter/issues/61875 Change-Id: I8477811b5e4d2003ec58b3aafc3a1c76668057ff Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/4561 Reviewed-by: Nurhan Turgut <nurhan@google.com> Reviewed-by: Christopher Fujino <fujino@google.com> Commit-Queue: Aaron Clarke <aaclarke@google.com>