[React Native] Disable audio levels

The audio levels are gathered by lib-jitsi-meet via polling of
RTCPeerConnection.getStats() which is very slow on Android. Since the
mobile app makes no use of audio levels, it is easiest to disable them
for now in order to not penalize the app.

react/features/base/lib-jitsi-meet/reducer.js

  */
 const INITIAL_STATE = {
     config: {
-        // FIXME Lib-jitsi-meet uses HTML script elements to asynchronously
-        // load certain pieces of JavaScript. Unfortunately, the technique
-        // doesn't work on React Native (because there are no HTML elements
-        // in the first place). Fortunately, these pieces of JavaScript
-        // currently involve third parties and we can temporarily disable
-        // them (until we implement an alternative to async script elements
-        // on React Native).
+        // FIXME The support for audio levels in lib-jitsi-meet polls the
+        // statistics of WebRTC at a short interval multiple times a second.
+        // Unfortunately, React Native is slow to fetch these statistics from
+        // the native WebRTC API, through the React Native bridge and eventually
+        // to JavaScript. Because the audio levels are of no interest to the
+        // mobile app, it is fastest to merely disable them.
+        disableAudioLevels: true,
+
+        // FIXME Lib-jitsi-meet uses HTML script elements to asynchronously load
+        // certain pieces of JavaScript. Unfortunately, the technique doesn't
+        // work on React Native (because there are no HTML elements in the first
+        // place). Fortunately, these pieces of JavaScript currently involve
+        // third parties and we can temporarily disable them (until we implement
+        // an alternative to async script elements on React Native).
         disableThirdPartyRequests: true
     },
     initializationError: null,