Signed-off-by: Rémy Coutable <remy@rymai.me>

The change in !11728 would cause an arbitrary project to be chosen to test
system hooks, and it's likely that the project would not have any commits or
relevant commits to test the hook. This would prevent admins from verifying
that the hook fired. Instead of trying to create a representative hook
dynamically, just send static data to guarantee the hook will actually be
tested.

Closes #37067

An upcoming update to rubocop-gitlab-security added additional
violations.