Service accounts currently have a unique email and username pattern that allows them to be identified easily. However there are use cases when the users would want to customize the email/username to pattern match them based on their namespace. For instance https://gitlab.com/gitlab-com/account-management/emea/dwp/-/issues/88#note_1436713617. This task is to enhance the the current behaviour by optionally allowing users to add in a custom email address (though the account will start with a default-generated address) ### Proposal 1. Modify the `Create Service Account User` [API](https://docs.gitlab.com/ee/api/groups.html#create-service-account-user) to have new optional parameters: - Username - E~~mail Address (?)~~ descoped and moved to https://gitlab.com/gitlab-org/gitlab/-/issues/451032+ - Name Preserve existing logic that automatically populates defaults if no naming parameters are passed. ~~2. Add `service account` pill badge, similar to this, but gray, to any service account in the UI: \<--- This has been moved to a separate story~~