Fix NUMBER_EMOJIS breakages inside Audio

[Kreusada]

Description of the changes

Closes #6169, fixes where the code attempts to mutate the now immutable NUMBER_EMOJIS.

Have the changes in this PR been tested?

Yes

[aikaterna]

After testing this change I ran into another issue on the next line:

[08:44:28] ERROR [red] AttributeError
Traceback (most recent call last)
/Users/aikaterna/red38/lib/python3.8/site-packages/discord/ext/commands/core.py:229 in wrapped
❱ 229 ret = await coro(*args, **kwargs)
/Users/aikaterna/red38/lib/python3.8/site-packages/redbot/cogs/audio/core/commands/playlists.py:830 in command_playlist_info
❱ 830 playlist, playlist_arg, scope = await self.get_playlist_match(
/Users/aikaterna/red38/lib/python3.8/site-packages/redbot/cogs/audio/core/utilities/playlists.py:267 in get_playlist_match
❱ 267 emojis.append("\N{CROSS MARK}")

AttributeError: 'tuple' object has no attribute 'append'

You could do something like this to resolve it:

emojis = available_emojis[: len(correct_scope_matches)]
emojis += ("\N{CROSS MARK}",)

I'm not going to add this as a suggestion in case there is a cleaner way to do this or another way you'd like to go about it.

[Jackenmen]

I switched this to a simple list() call which should make it work as it would have before, thanks for the PR.