message: fix remote UI when dropping a new .hdr ibl file
  the ibl wasn't updated in internal structures
  the previous ibl was leaked
diff: @@ -221,8 +221,13 @@ class MainActivity : Activity() {
  equirectToCubemap.destroy();
  context.destroy();
  + // destroy the previous IBl
  + engine.destroyIndirectLight(modelViewer.scene.indirectLight!!);
  + engine.destroySkybox(modelViewer.scene.skybox!!);
  +
  modelViewer.scene.skybox = sky
  modelViewer.scene.indirectLight = ibl
  + viewerContent.indirectLight = ibl
  }
  }
  }
  