feat(stats): enable RTPStatsCollector for RN

Enables RTPStatsCollector for react-native. The getStats method was
supported long time ago, but the stats produced by the RTPStatsCollector
were not consumed. Now they are needed for the automated testing on RN.

modules/statistics/RTPStatsCollector.js

         || browser.isOpera() || browser.isFirefox()
         || browser.isNWJS() || browser.isElectron()
         || browser.isTemasysPluginUsed() || browser.isEdge()
-        || browser.isSafariWithWebrtc();
+        || browser.isSafariWithWebrtc() || browser.isReactNative();
 
 /**
  * The lib-jitsi-meet browser-agnostic names of the browser-specific keys