User who is not a member of a project is able to add meta data upon issue creation
Problem
We introduced the ability for Project Members with the role of Guest to add meta-data when creating a new issue (and only when) via !62816 (merged).
This issue (https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/6269) was recently opened where the author was not a member of the project in any capacity but was able to set assignees, milestone, and labels.