Merge branch 'fix/471717-empty-changelog-config-yaml' into 'master'

Prevent 500 errors when evaluating empty changelog configs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/166610



Merged-by: Joe Woodward <jwoodward@gitlab.com>
Approved-by: Naman Jagdish Gala <ngala@gitlab.com>
Approved-by: Eugie Limpin <elimpin@gitlab.com>
Co-authored-by: Joe Woodward <j@joewoodward.me>