Update gb-mobile ref, don't use React classes

Author: hypest

libs/editor/WordPressEditor/src/main/java/org/wordpress/android/editor/GutenbergEditorFragment.java

@@ -32,7 +32,6 @@
 import androidx.lifecycle.LiveData;
 
 import com.android.volley.toolbox.ImageLoader;
-import com.facebook.react.bridge.ReadableArray;
 
 import org.wordpress.android.util.AppLog;
 import org.wordpress.android.util.AppLog.T;
@@ -271,7 +270,7 @@ public void onQueryCurrentProgressForUploadingMedia() {
                 },
                 new OnEditorMountListener() {
                     @Override
-                    public void onEditorDidMount(ReadableArray unsupportedBlocks) {
+                    public void onEditorDidMount(ArrayList<Object> unsupportedBlocks) {
                         mEditorDidMount = true;
                         mEditorFragmentListener.onEditorFragmentContentReady(unsupportedBlocks.size() > 0);