Fix UI error when leaving the lobby too quickly

[NachosChipeados]

Fixes #849, using the fix suggested by @Jan200101

How to test:

1. Click "Launch Northstar"
2. When the lobby starts loading and you can see you character, immediately press "right arrow + space", to join a private match.
   Without this pr, the game would kick you to the main menu. With this pr, no kick

Before:
https://github.com/user-attachments/assets/2447566b-68ae-4be5-8f22-35b45b7c094b

After:
https://github.com/user-attachments/assets/b59a50b7-ec12-4df5-82a5-78ed66769c70

[GeckoEidechse]

cc @Bobbyperson you might be able to verify this 👀

[Bobbyperson]

yippie!!! i'll test when i get home

[Zanieon]

Sorry but this fix is not the way to solve #849 i addressed it to myself because the problem does not lie in the sh_loadouts script, it lies in how @ASpoonPlaysGames wrote the sh_progression script, this error comes from a threaded function that waits a solid second before registering the persistent loadouts, the validity check needs to be put in there.

[JMM889901]

Like @Zanieon said, this should probably be moved to sh_progression:172 to fix that specific issue, Though its arguably worth having a check here in general since something else could call it wrong (though I'd rather it fail if we are passing invalid entities here, there is no reason we should be)

[NachosChipeados]

Moving the check to sh_progression doesn't seem to fix it on my end. I'm probably doing something wrong

Titanfall.2.2024-10-12.22-47-32.mp4

[NachosChipeados]

Nevermind, i was just being stupid. It works now