Validate default VSA stage name
What does this MR do and why?
This MR ensures that the default VSA stage name is consistent with the names defined in the default stage list: https://gitlab.com/gitlab-org/gitlab/-/tree/master/lib/gitlab/analytics/cycle_analytics/default_stages.rb
The previous implementation was raising an error, this MR adds an active record validation.
Related to #432346 (closed)
Edited by Adam Hegyi