Report DOMException when audio output device change fails as gUM error to callstats

JitsiConference.js

         this.statistics.sendGetUserMediaFailed(error);
     }.bind(this));
     JitsiMeetJS._globalOnErrorHandler.push(function(error) {
-        this.statistics.sendUnhandledError(error);
+        if (error instanceof JitsiTrackError && error.gum) {
+            this.statistics.sendGetUserMediaFailed(error);
+        } else {
+            this.statistics.sendUnhandledError(error);
+        }
     }.bind(this));
     this.participants = {};
     this.lastDominantSpeaker = null;
                 conference.statistics.sendIceConnectionFailedEvent(pc);
                 conference.room.eventEmitter.emit(
                     XMPPEvents.CONFERENCE_SETUP_FAILED,
-                    new Error("ICE fail")); 
+                    new Error("ICE fail"));
             });
 
         conference.rtc.addListener(RTCEvents.TRACK_ATTACHED,

JitsiMeetJS.js

               handler(error);
           });
         } else {
-            Statistics.sendUnhandledError(error);
+            if (error instanceof JitsiTrackError && error.gum) {
+                Statistics.sendGetUserMediaFailed(error);
+            } else {
+                Statistics.sendUnhandledError(error);
+            }
         }
     },
 

JitsiTrackError.js

  * @param {Object|string} error - error object or error name
  * @param {Object|string} (options) - getUserMedia constraints object or error
  *      message
- * @param {('audio'|'video'|'desktop'|'screen')[]} (devices) - list of
- *      getUserMedia requested devices
+ * @param {('audio'|'video'|'desktop'|'screen'|'audiooutput')[]} (devices) -
+ *      list of getUserMedia requested devices
  */
 function JitsiTrackError(error, options, devices) {
     if (typeof error === "object" && typeof error.name !== "undefined") {

doc/API.md

 exposes additional ```"gum"``` property, which is an object with following properties:
  - error - original GUM error
  - constraints - GUM constraints object used for the call
- - devices - array of devices requested in GUM call (possible values - "audio", "video", "screen", "desktop")
+ - devices - array of devices requested in GUM call (possible values - "audio", "video", "screen", "desktop", "audiooutput")
 
 Getting Started
 ==============

modules/RTC/RTCUtils.js

             stream.getAudioTracks && stream.getAudioTracks().length) {
             element.setSinkId(RTCUtils.getAudioOutputDevice())
                 .catch(function (ex) {
+                    var err = new JitsiTrackError(ex, null, ['audiooutput']);
+
                     GlobalOnErrorHandler.callUnhandledRejectionHandler(
-                        {promise: this, reason: ex});
+                        {promise: this, reason: err});
+
                     logger.warn('Failed to set audio output device for the ' +
                         'element. Default audio output device will be used ' +
                         'instead',
-                        element, ex);
+                        element, err);
                 });
         }
 
             disableNS = options.disableNS;
             logger.info("Disable NS: " + disableNS);
         }
-        
+
         return new Promise(function(resolve, reject) {
             if (RTCBrowserType.isFirefox()) {
                 var FFversion = RTCBrowserType.getFirefoxVersion();