Add comments to .ci.yaml that were removed from recipes. (#129321)

Firebaselab recipe was cleaned up and comments removed. This is adding the still valid comments to the .ci.yaml file.
https://dart.googlesource.com/external/github.com/flutter/flutter/+/f582c0c573e2b86c985a2b4bdebb7a0109662fca
1 file changed
tree: 984166778c8c4ba72697b4581748c9de7a9cac4e
  1. commits.json