[release-12.0.2] Alerting: Provisioning API returns 403 on quota exceeded for rule group PUT (#106477)

Alerting: Provisioning API returns 403 on quota exceeded for rule group PUT (#106409)

(cherry picked from commit 1df888c517)

Co-authored-by: Vadim Stepanov <vstpme@gmail.com>

pkg/services/ngalert/api/api_provisioning.go

@@ -515,6 +515,9 @@ func (srv *ProvisioningSrv) RoutePutAlertRuleGroup(c *contextmodel.ReqContext, a
 	if errors.Is(err, store.ErrOptimisticLock) {
 		return ErrResp(http.StatusConflict, err, "")
 	}
+	if errors.Is(err, alerting_models.ErrQuotaReached) {
+		return ErrResp(http.StatusForbidden, err, "")
+	}
 	if err != nil {
 		return response.ErrOrFallback(http.StatusInternalServerError, "", err)
 	}