feat(base/config): notify user on conference destruction option (#15697)

Notify user about conference destruction using a new config option.

conference.js

@@ -2278,8 +2278,10 @@ export default {
      * @param {boolean} [requestFeedback=false] if user feedback should be
      * @param {string} [hangupReason] the reason for leaving the meeting
      * requested
+     * @param {boolean} [notifyOnConferenceTermination] whether to notify
+     * the user on conference termination
      */
-    hangup(requestFeedback = false, hangupReason) {
+    hangup(requestFeedback = false, hangupReason, notifyOnConferenceTermination) {
         APP.store.dispatch(disableReceiver());
 
         this._stopProxyConnection();
@@ -2298,7 +2300,7 @@ export default {
 
         if (requestFeedback) {
             const feedbackDialogClosed = (feedbackResult = {}) => {
-                if (!feedbackResult.wasDialogShown && hangupReason) {
+                if (!feedbackResult.wasDialogShown && hangupReason && notifyOnConferenceTermination) {
                     return APP.store.dispatch(
                         openLeaveReasonDialog(hangupReason)).then(() => feedbackResult);
                 }