[results feed] Add comment message definition to the protobuf file describing the database
[results feed] Add comment message definition to the protobuf file describing the database

Change-Id: Ibd86d0661d69246328bea2e92d72665ed3ba1a6d
Reviewed-on: https://dart-review.googlesource.com/c/dart_ci/+/124180
Reviewed-by: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>

dart-lang/dart_ci,dart-lang/dart_ci,dart-lang/dart_ci,dart-lang/dart_ci