[release-12.1.1] Alerting: Add rule group name validation to the Prometheus conversion API (#108767)

Alerting: Add rule group name validation to the Prometheus conversion API (#108740)

Alerting: Add rule group name validation to the conversion API
(cherry picked from commit f969eb0277)

Co-authored-by: Alexander Akhmetov <me@alx.cx>

pkg/services/ngalert/api/api_convert_prometheus_test.go

@@ -291,6 +291,30 @@ func TestRouteConvertPrometheusPostRuleGroup(t *testing.T) {
 		}
 	})
 
+	t.Run("with empty rule group name should return 400", func(t *testing.T) {
+		srv, _, _ := createConvertPrometheusSrv(t)
+		rc := createRequestCtx()
+
+		emptyNameGroup := apimodels.PrometheusRuleGroup{
+			Name:     "",
+			Interval: prommodel.Duration(1 * time.Minute),
+			Rules: []apimodels.PrometheusRule{
+				{
+					Alert: "TestAlert",
+					Expr:  "up == 0",
+					For:   util.Pointer(prommodel.Duration(5 * time.Minute)),
+					Labels: map[string]string{
+						"severity": "critical",
+					},
+				},
+			},
+		}
+
+		response := srv.RouteConvertPrometheusPostRuleGroup(rc, "test", emptyNameGroup)
+		require.Equal(t, http.StatusBadRequest, response.Status())
+		require.Contains(t, string(response.Body()), "rule group name must not be empty")
+	})
+
 	t.Run("with valid request should return 202", func(t *testing.T) {
 		srv, _, _ := createConvertPrometheusSrv(t)
 		rc := createRequestCtx()