Log warning instead of error for audio output device change errors

conference.js

                 APP.settings.setAudioOutputDeviceId(audioOutputDeviceId)
                     .then(() => console.log('changed audio output device'))
                     .catch((err) => {
-                        console.error('failed to set audio output device', err);
+                        console.warn('Failed to change audio output device. ' +
+                            'Default or previously set audio output device ' +
+                            'will be used instead.', err);
                     });
             }
         );

modules/settings/Settings.js

         JitsiMeetJS.mediaDevices.getAudioOutputDevice()) {
         JitsiMeetJS.mediaDevices.setAudioOutputDevice(audioOutputDeviceId)
             .catch((ex) => {
-                console.error('failed to set audio output device from local ' +
-                    'storage', ex);
+                console.warn('Failed to set audio output device from local ' +
+                    'storage. Default audio output device will be used' +
+                    'instead.', ex);
             });
     }
 } else {