Can't launch itch.io version from Steam (Linux)

### My mods and Everest install are up to date

Yes

### I have recreated the bug with only Everest OR a minimum number of mods enabled

Yes

### Describe the bug

I have installed Everest to my itch.io copy of Celeste. When I open the "Celeste" executable it works, but I have added the executable to Steam and it won't launch. Doesn't matter if I have any mods enabled. It also doesn't generate any log.txt in the Celeste folder if I do this. It used to work, so I assume an Everest update broke it.

### Steps to reproduce

- Install Celeste from itch.io
- Install latest Everest using Olympus
- Add Celeste to Steam
- Click Play

### Expected behavior

Launches the game.

### Operating System

KDE Neon 5.27

### Everest Version

4607

### Mods required to reproduce

_No response_

### Additional context

_No response_