LastImportTime for resource. (#112153)

* LastImportTime for resource.

* Make StorageBackendImpl implement GetResourceLastImportTimes

* More missing implementations of GetResourceLastImportTimes

* Fix import.

* Skip TestGetResourceLastImportTime in TestBadgerKVStorageBackend.

* Implement GetResourceLastImportTimes by mockStorageBackend

* Bump test tolerance.

* Fix postgres query and timezone.

* Fix postgres query and timezone.

* Make linter happy.

pkg/storage/unified/resource/storage_backend.go

@@ -15,12 +15,13 @@ import (
 
 	"github.com/bwmarrin/snowflake"
 	"github.com/grafana/grafana-app-sdk/logging"
-	"github.com/grafana/grafana/pkg/apimachinery/utils"
-	"github.com/grafana/grafana/pkg/storage/unified/resourcepb"
-	"github.com/grafana/grafana/pkg/util/debouncer"
 	"github.com/prometheus/client_golang/prometheus"
 	"go.opentelemetry.io/otel/trace"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	"github.com/grafana/grafana/pkg/apimachinery/utils"
+	"github.com/grafana/grafana/pkg/storage/unified/resourcepb"
+	"github.com/grafana/grafana/pkg/util/debouncer"
 )
 
 const (
@@ -1076,6 +1077,12 @@ func (k *kvStorageBackend) GetResourceStats(ctx context.Context, namespace strin
 	return k.dataStore.GetResourceStats(ctx, namespace, minCount)
 }
 
+func (k *kvStorageBackend) GetResourceLastImportTimes(ctx context.Context) iter.Seq2[ResourceLastImportTime, error] {
+	return func(yield func(ResourceLastImportTime, error) bool) {
+		yield(ResourceLastImportTime{}, fmt.Errorf("not implemented"))
+	}
+}
+
 // readAndClose reads all data from a ReadCloser and ensures it's closed,
 // combining any errors from both operations.
 func readAndClose(r io.ReadCloser) ([]byte, error) {