Prefer Flow development mode over localhost check (#26)

After 5673bd3 `Vaadin.developmentMode` is always true for localhost even if flow is running in production mode.

vaadin-development-mode-detector.html

@@ -21,14 +21,14 @@
         return true;
       }
 
-      if (!isLocalhost()) {
-        return false;
-      }
-
       if (FlowClients) {
         return !isFlowProductionMode();
       }
 
+      if (!isLocalhost()) {
+        return false;
+      }
+
       return !isMinified();
     } catch (e) {
       // Some error in this code, assume production so no further actions will be taken