Alerting: Update API to use folders' full paths (#81214)

* update GetUserVisibleNamespaces to use FolderSeriver
* update GetNamespaceByUID to use FolderService.GetFolders
* update GetAlertRulesForScheduling to use FolderService.GetFolders 

* Update API and GetAlertRulesForScheduling to use the folder's full path
* get full path of folder in RouteTestGrafanaRuleConfig

* fix escaping of titles for MySQL

pkg/services/ngalert/api/api.go

@@ -129,6 +129,7 @@ func (api *API) RegisterAPIEndpoints(m *metrics.API) {
 			featureManager:  api.FeatureManager,
 			appUrl:          api.AppUrl,
 			tracer:          api.Tracer,
+			folderService:   api.RuleStore,
 		}), m)
 	api.RegisterConfigurationApiEndpoints(NewConfiguration(
 		&ConfigSrv{