Disallow refreshing when there is no query VC

MongoView/View Controllers/DatabaseViewController.swift

@@ -160,7 +160,7 @@ class DatabaseViewController: NSViewController {
 
 extension DatabaseViewController: NSMenuItemValidation {
     func validateMenuItem(_ menuItem: NSMenuItem) -> Bool {
-        if menuItem.action == #selector(runQuery(_:)) {
+        if menuItem.action == #selector(runQuery(_:)) || menuItem.action == #selector(refresh(_:)) {
             return queryViewController != nil
         }
         return true