chore : Deprecating FeatureToggles.IsEnabledGlobally (#112885)

* add deprecation on featuremgmt.IsEnabledGlobally

* add nolint reason

* add reasonable deprecation message

* remove junk edits

* add more nolints

* addressing review comments

* Update pkg/services/featuremgmt/models.go

Co-authored-by: Dave Henderson <dave.henderson@grafana.com>

---------

Co-authored-by: Dave Henderson <dave.henderson@grafana.com>

pkg/services/cloudmigration/cloudmigrationimpl/cloudmigration.go

@@ -119,6 +119,7 @@ func ProvideService(
 	libraryElementsService libraryelements.Service,
 	ngAlert *ngalert.AlertNG,
 ) (cloudmigration.Service, error) {
+	//nolint:staticcheck // not yet migrated to OpenFeature
 	if !features.IsEnabledGlobally(featuremgmt.FlagOnPremToCloudMigrations) {
 		return &NoopServiceImpl{}, nil
 	}