Update DangerBot message to be more strict post release of new subscription card UI
Problem
After the subscription card UI is rolled out for all types of subscriptions i.e. after completing - #6539 (closed), #7473 (closed) and https://gitlab.com/gitlab-org/customers-gitlab-com/-/issues/6962 we need to update the DangerBot message added here to be more strict and to let the MR author know that the old files are now depreciated and no changes should be made to those files. These files will be eventually removed in Cleanup of old subscription card display (&10903), but till then we should have some warning message if anyone tries to update these files for the old subscription card UI.
Proposal
Result
Next steps (if any)
How will we measure success?
Edited by Sharmad Nachnolkar