Unified: Run resource data migrations at startup (#114857)

* chore: uncomment unified migration

* chore: adapt and fix tests

* chore: dynamically bump max conns if needed during migration

* chore: copilot suggestions

* chore: pass ctx in RegisterMigration

* chore: make playlists opt-out and dashboards opt-in

* chore: adjust dashboard test

* chore: disable enable log in test

* chore: address review comments

- do not use pointer config
- add migration registry

* chore: more consistent naming

* chore: fix playlist discovery test

pkg/tests/apis/collections/stars_test.go

@@ -42,9 +42,10 @@ func TestIntegrationStars(t *testing.T) {
 		}
 
 		helper := apis.NewK8sTestHelper(t, testinfra.GrafanaOpts{
-			AppModeProduction:    false, // required for experimental APIs
-			DisableAnonymous:     true,
-			EnableFeatureToggles: flags,
+			DisableDataMigrations: true,
+			AppModeProduction:     false, // required for experimental APIs
+			DisableAnonymous:      true,
+			EnableFeatureToggles:  flags,
 			UnifiedStorageConfig: map[string]setting.UnifiedStorageConfig{
 				"dashboards.dashboard.grafana.app": {
 					DualWriterMode: mode,