Add MR trigger by default for Duo Developer
## Problem With the changes from https://gitlab.com/gitlab-org/gitlab/-/work_items/589246 Duo Developer will be able to iterate on the changes from an MR after it is mentioned. However, users will need to manually add the "mention" trigger to Duo Developer to make this happen ## Desired Outcome Mention trigger is automatically active for any Duo Developer, whether it was already activated or it is added newly to the project.
issue