fix(moderator): use 'enableLipSync' from the connection options

Because the flag is required in the connection options anyway it will
be better to use it from one options set only to avoid redundancy.

modules/xmpp/moderator.js

                 value: true
             }).up();
     //}
-    if (this.options.conference.enableLipSync !== undefined) {
+    if (this.options.connection.enableLipSync !== undefined) {
         elem.c(
             'property', {
                 name: 'enableLipSync',
-                value: this.options.conference.enableLipSync
+                value: this.options.connection.enableLipSync
             }).up();
     }
     if (this.options.conference.audioPacketDelay !== undefined) {