Don't even bother checking touch.id == 0 for closing popup windows. It's fine to close with any touch.

Fixes issue with touch on Windows mentioned in #14387

Also includes a warning fix.

Common/UI/UIScreen.cpp

@@ -222,7 +222,7 @@ PopupScreen::PopupScreen(std::string title, std::string button1, std::string but
 }
 
 bool PopupScreen::touch(const TouchInput &touch) {
-	if (!box_ || (touch.flags & TOUCH_DOWN) == 0 || touch.id != 0) {
+	if (!box_ || (touch.flags & TOUCH_DOWN) == 0) {
 		return UIDialogScreen::touch(touch);
 	}