fix: Skips sending an extra presence on join. (#1174)

* fix: Skips sending an extra presence on join.

* Renames the variable names.

JitsiConference.js

  */
 JitsiConference.prototype.setDisplayName = function(name) {
     if (this.room) {
-        // remove previously set nickname
-        this.room.removeFromPresence('nick');
-
         this.room.addToPresence('nick', {
             attributes: { xmlns: 'http://jabber.org/protocol/nick' },
             value: name
         return;
     }
     this.startMutedPolicy = policy;
-    this.room.removeFromPresence('startmuted');
     this.room.addToPresence('startmuted', {
         attributes: {
             audio: policy.audio,

modules/xmpp/ChatRoom.js

                 }
             });
         }
+
+        this.presenceUpdateTime = Date.now();
     }
 
     /**
         }
 
         parser.json2packet(this.presMap.nodes, pres);
+
+        // we store time we last synced presence state
+        this.presenceSyncTime = Date.now();
+
         this.connection.send(pres);
         if (fromJoin) {
             // XXX We're pressed for time here because we're beginning a complex
 
                 // Re-send presence in case any presence updates were added,
                 // but blocked from sending, during the join process.
-                this.sendPresence();
+                // send the presence only if there was a modification after we had synced it
+                if (this.presenceUpdateTime >= this.presenceSyncTime) {
+                    this.sendPresence();
+                }
 
                 this.eventEmitter.emit(XMPPEvents.MUC_JOINED);
 
     /* eslint-enable max-params */
 
     /**
-     *
+     * Adds the key to the presence map, overriding any previous value.
      * @param key
      * @param values
      */
         values.tagName = key;
         this.removeFromPresence(key);
         this.presMap.nodes.push(values);
+        this.presenceUpdateTime = Date.now();
     }
 
     /**
-     * Retreives a value from the presence map.
+     * Retrieves a value from the presence map.
      *
      * @param {string} key - The key to find the value for.
      * @returns {Object?}
     }
 
     /**
-     *
+     * Removes a key from the presence map.
      * @param key
      */
     removeFromPresence(key) {
         const nodes = this.presMap.nodes.filter(node => key !== node.tagName);
 
         this.presMap.nodes = nodes;
+        this.presenceUpdateTime = Date.now();
     }
 
     /**
      * @param mute
      */
     addAudioInfoToPresence(mute) {
-        this.removeFromPresence('audiomuted');
         this.addToPresence(
             'audiomuted',
             {
      * @param mute
      */
     addVideoInfoToPresence(mute) {
-        this.removeFromPresence('videomuted');
         this.addToPresence(
             'videomuted',
             {