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/api/alerting/api_convert_prometheus_test.go

@@ -1166,11 +1166,12 @@ func TestIntegrationConvertPrometheusEndpoints_Editor(t *testing.T) {
 	testinfra.SQLiteIntegrationTest(t)
 
 	dir, gpath := testinfra.CreateGrafDir(t, testinfra.GrafanaOpts{
-		DisableLegacyAlerting: true,
-		EnableUnifiedAlerting: true,
-		DisableAnonymous:      true,
-		AppModeProduction:     true,
-		EnableRecordingRules:  true,
+		DisableAuthZClientCache: true,
+		DisableLegacyAlerting:   true,
+		EnableUnifiedAlerting:   true,
+		DisableAnonymous:        true,
+		AppModeProduction:       true,
+		EnableRecordingRules:    true,
 	})
 
 	grafanaListedAddr, env := testinfra.StartGrafanaEnv(t, dir, gpath)