Gitlab: Update to 15.8.1

Big Bang

Fix gitlab values template. Had wrong logic for Gitlab SSO enabled with global sso settings.

Package Changes

https://repo1.dso.mil/big-bang/apps/developer-tools/gitlab/-/blob/6.8.1-bb.0/CHANGELOG.md

Package MR

https://repo1.dso.mil/big-bang/apps/developer-tools/gitlab/-/merge_requests/173

For Issue

Closes https://repo1.dso.mil/big-bang/apps/developer-tools/gitlab/-/issues/173