Handle UIB interactions for ignoring channels.

[Kowlin]

Description of the changes

Fixes #6501, this PR handles User Installed Bot interactions where they will error out on trying to check from Threads, as it cannot get the channels it need. Furthermore, this handling like this will NOT check for categories, as the bot cannot gather those from a context where it can only get information from the interaction. Tough luck...

Have the changes in this PR been tested?

Yes, but only internally, this must be tested by trying to reproduce the original error from #6501

[Flame442]

Fixes the issues for pure app commands, but there is still a remaining error for hybrids in particular. Not sure if we want to just fix that here, or if we want to save that for another PR.

File "venv\lib\site-packages\redbot\core\_global_checks.py", line 8, in check_message_is_eligible_as_command
    return await ctx.bot.message_eligible_as_command(ctx.message)
  File "venv\lib\site-packages\redbot\core\bot.py", line 844, in message_eligible_as_command
    if not can_user_send_messages_in(guild.me, channel):
  File "venv\lib\site-packages\redbot\core\utils\__init__.py", line 724, in can_user_send_messages_in
    perms = channel.permissions_for(obj)
  File "venv\lib\site-packages\discord\threads.py", line 425, in permissions_for
    raise ClientException('Parent channel not found')
discord.errors.ClientException: Parent channel not found

[Kowlin]

Hybirds are now handled properly!

[Jackenmen]

I'm only really concerned about proper documentation here - there used to be just one flow that everything went through. Now that we continue to have to fix things for various interactions and the implementation is split between different places, it would be good to inform the code reader about the traps - see the review comment for a specific suggestion.
It might also be worth updating help text / messages from the [p]ignore command such that the user knows that the category ignores won't apply to user-installed commands.

[Jackenmen]

I think we should add a comment here and possibly also in Red.message_eligible_as_command so that we don't introduce discrepancies when changing the logic in the future:

Suggested change

	if ctx.interaction is not None:
	return True
	if ctx.interaction is not None:
	# equivalent checks are performed by `RedTree.interaction_check`
	return True