Leaving ?debugLocalScene on a custom scene breaks regular room loading.

[Exairnous]

Description
If you enable ?debugLocalScene and upload a GLB scene to the room, then attempt to load the room without that flag (and without changing the scene back to a regular scene) the room will get stuck on loading the scene and fail to load.

To Reproduce
Steps to reproduce the behavior:

1. Load a room with the ?debugLocalScene flag
2. Drag and drop a GLB into the room to switch it to a local scene.
3. Load the room again, this time without the ?debugLocalScene flag
4. The room will get stuck on loading the scene and never finish.

Expected behavior
The room should either load to the default blue ground plane with black sky (like it does if you reload the room with the ?debugLocalScene flag), or present some kind of warning with a description of how to fix it, or a dialog allowing you to change the scene, or something along those lines.

Hardware

• Device: Laptop
• OS: Linux
• Browser: Firefox

Additional context
Workaround:

1. Load the hanging room with the ?debugLocalScene flag.
2. Change the scene via the "Room Info and Settings" panel to a permanently uploaded scene (e.g. one of the featured scenes)
3. You should now be able to load the room without the ?debugLocalScene flag.