Remove `multiple_code_owner_rules` feature flag
What does this MR do?
Before we were creating a single ApprovalRule
called "Code
Owner". But when we introduced multiple_code_owner_rules
we were
creating a rule per entry in the CODEOWNERS file and displaying that.
Having the feature flag meant having to support the 2 datamodels. This removes the feature flag and gets rid of the legacy code that was there to support it's off-state.
Does this MR meet the acceptance criteria?
Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/9623
Conformity
Edited by Bob Van Landuyt