[BUG] Inconsistent fetch_* function behaviour

[Kigstn]

Describe the bug
Not all .fetch_* instances return None optionally. Some raise not found errors.

Someone needs to go through all methods and make sure the NotFound exception is caught and None is returned everywhere. Currently it's 50/50

This is needed everywhere

        try:
            return await self.cache.fetch_member(guild_id, user_id)
        except NotFound:
            return None 

[benwoo1110]

https://github.com/Discord-Snake-Pit/Dis-Snek/blob/07cf9445daaebb4b122744c91b1a8236a21269d9/dis_snek/models/discord/guild.py#L1300-L1315
hmm should fetch_ban return None?