[BUG]: Failing to account for get_user returning None.

[Qwerty-133]

Bot Version

v3.10.2

How are you hosting Modmail?

Other

Error Logs

https://paste.pythondiscord.com/nepupiwime.txt?noredirect

Screenshots

No response

Additional Information

This happens when the bot is trying to close pending threads but the cache doesn't contain the users who scheduled the closing.