fix: make data syncer run configurable on mode (2->3) change (#104401)

pkg/setting/setting.go

@@ -556,6 +556,7 @@ type Cfg struct {
 type UnifiedStorageConfig struct {
 	DualWriterMode                       rest.DualWriterMode
 	DualWriterPeriodicDataSyncJobEnabled bool
+	DualWriterMigrationDataSyncDisabled  bool
 	// DataSyncerInterval defines how often the data syncer should run for a resource on the grafana instance.
 	DataSyncerInterval time.Duration
 	// DataSyncerRecordsLimit defines how many records will be processed at max during a sync invocation.