CloudMigrations: Store encryption key in unified secrets table (#90908)

* store encryption key in unified secrets table

* fix local dev mode

* make metadata more realistic

* fix tests

* fix sql queries against postgres

* fix stats endpoint

pkg/services/cloudmigration/cloudmigrationimpl/cloudmigration_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/folder"
 	"github.com/grafana/grafana/pkg/services/folder/foldertest"
 	secretsfakes "github.com/grafana/grafana/pkg/services/secrets/fakes"
+	secretskv "github.com/grafana/grafana/pkg/services/secrets/kvstore"
 	"github.com/grafana/grafana/pkg/services/user"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/prometheus/client_golang/prometheus"
@@ -438,6 +439,7 @@ func setUpServiceTest(t *testing.T, withDashboardMock bool) cloudmigration.Servi
 			featuremgmt.FlagDashboardRestore),
 		sqlStore,
 		dsService,
+		secretskv.NewFakeSQLSecretsKVStore(t),
 		secretsService,
 		rr,
 		prometheus.DefaultRegisterer,