FS-8591 [verto_communicator] restoring chat send button behavior

html5/verto/verto_communicator/src/vertoControllers/controllers/ChatController.js

+
 (function() {
   'use strict';
 
@@ -199,7 +200,9 @@
         // Only conferencing chat is supported for now
         // but still calling method with the conference prefix
         // so we know that explicitly.
-        event.preventDefault();
+        if (event && event.type == 'keydown') {
+          event.preventDefault();
+        }
         verto.sendConferenceChat($scope.message);
         $scope.message = CLEAN_MESSAGE;
       };