On reload, references to Metrics within classes in the Gitlab::Metrics module fail. Update all references to ::Gitlab::Metrics so that constant lookup finds the right module in development. This fix should not impact production.
Enables frozen string for the following: * lib/gitlab/hook_data/**/*.rb * lib/gitlab/i18n/**/*.rb * lib/gitlab/import/**/*.rb * lib/gitlab/import_export/**/*.rb * lib/gitlab/kubernetes/**/*.rb * lib/gitlab/legacy_github_import/**/*.rb * lib/gitlab/manifest_import/**/*.rb * lib/gitlab/metrics/**/*.rb * lib/gitlab/middleware/**/*.rb Partially addresses gitlab-org/gitlab-ce#47424.
+ fix tests after metrics rename