[mirotalksfu] - refactoring and fix

public/js/VideoGrid.js

@@ -169,7 +169,7 @@ function resizeMainButtons() {
 // ####################################################
 
 function resizeChatRoom() {
-    if (DetectRTC.isMobileDevice || !rc.isChatOpen || rc.isChatPinned) return;
+    if (!rc || rc.isMobileDevice || !rc.isChatOpen || rc.isChatPinned) return;
 
     const windowWidth = window.innerWidth;
     const windowHeight = window.innerHeight;