Marked variable muted as final to fix compilation issue

android/src/main/java/com/syan/agora/AgoraModule.java

          * 用户mute音频回调
          */
         @Override
-        public void onUserMuteAudio(final int uid, boolean muted) {
+        public void onUserMuteAudio(final int uid, final boolean muted) {
             runOnUiThread(new Runnable() {
                 @Override
                 public void run() {
          * 用户mute视频回调
          */
         @Override
-        public void onUserMuteVideo(final int uid, boolean muted) {
+        public void onUserMuteVideo(final int uid, final boolean muted) {
             runOnUiThread(new Runnable() {
                 @Override
                 public void run() {