[Android] Fix UnsupportedOperationException in AudioModeModule

android/sdk/src/main/java/org/jitsi/meet/sdk/AudioModeModule.java

 import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.bridge.WritableMap;
 
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
     /**
      * List of currently available audio devices.
      */
-    private Set<String> availableDevices = Collections.emptySet();
+    private Set<String> availableDevices = new HashSet<>();
 
     /**
      * Currently selected device.