Chore: Make Cfg field private in SQLStore (#85593)

* make cfg private in sqlstore

* fix db init in tests

* fix case

* fix folder test init

* fix imports

* make another Cfg private

* remove another Cfg

* remove unused variable

* use store cfg, it has side-effects

* fix mutated cfg in tests

pkg/services/annotations/annotationsimpl/loki/historian_store_test.go

@@ -42,8 +42,7 @@ func TestIntegrationAlertStateHistoryStore(t *testing.T) {
 		t.Skip("skipping integration test")
 	}
 
-	sql := db.InitTestDB(t)
-	cfg := sql.Cfg
+	sql, cfg := db.InitTestDBWithCfg(t)
 
 	dashboard1 := testutil.CreateDashboard(t, sql, cfg, featuremgmt.WithFeatures(), dashboards.SaveDashboardCommand{
 		UserID: 1,