fix: update search request for existing provisioned dashboards in modes 3+ (#114412)

Fix search for existing provisioned dashboards in modes 3+

The search query was not requesting the dashboard's "legacy ID". As a result,
the provisioning process would not find existing provisioned dashboards, making
copies of these dashboards every time there was a change in the provisioned
dashboard's definition.

pkg/services/dashboards/service/dashboard_service.go

@@ -2009,7 +2009,14 @@ func (dr *DashboardServiceImpl) searchDashboardsThroughK8sRaw(ctx context.Contex
 	request.Limit = query.Limit
 	request.Page = query.Page
 	request.Offset = (query.Page - 1) * query.Limit // only relevant when running in modes 3+
-	request.Fields = dashboardsearch.IncludeFields
+	request.Fields = append(
+		dashboardsearch.IncludeFields,
+		// Include the dashboard legacy ID in the results, as it is needed when
+		// determining whether a provisioned dashboard exists or not, see
+		// `(*DashboardServiceImpl).searchProvisionedDashboardsThroughK8s`.
+		resource.SEARCH_FIELD_LEGACY_ID,
+		resource.SEARCH_FIELD_LABELS+"."+resource.SEARCH_FIELD_LEGACY_ID,
+	)
 
 	namespace := dr.k8sclient.GetNamespace(query.OrgId)
 	var err error

pkg/services/dashboards/service/dashboard_service_test.go

@@ -2016,6 +2016,26 @@ func TestSearchDashboardsThroughK8sRaw(t *testing.T) {
 		_, err := service.searchDashboardsThroughK8s(ctx, query)
 		require.NoError(t, err)
 	})
+
+	t.Run("search will request legacy dashboard ID", func(t *testing.T) {
+		ctx := context.Background()
+		k8sCliMock := new(client.MockK8sHandler)
+		service := &DashboardServiceImpl{k8sclient: k8sCliMock}
+		query := &dashboards.FindPersistedDashboardsQuery{
+			ManagedBy: utils.ManagerKindClassicFP, //nolint:staticcheck
+			OrgId:     1,
+		}
+		k8sCliMock.On("GetNamespace", mock.Anything, mock.Anything).Return("default")
+		k8sCliMock.On("Search", mock.Anything, mock.Anything, mock.MatchedBy(func(req *resourcepb.ResourceSearchRequest) bool {
+			return slices.Contains(req.Fields, "grafana.app/deprecatedInternalID") &&
+				slices.Contains(req.Fields, "labels.grafana.app/deprecatedInternalID")
+		})).Return(&resourcepb.ResourceSearchResponse{
+			Results:   &resourcepb.ResourceTable{},
+			TotalHits: 0,
+		}, nil)
+		_, err := service.searchDashboardsThroughK8s(ctx, query)
+		require.NoError(t, err)
+	})
 }
 
 func TestSearchProvisionedDashboardsThroughK8sRaw(t *testing.T) {