[Audio] Ensure commands that need the voice channel can't be run by a user not in the voice channel

[Drapersniper]

FFS Draper you dumb son ...

Traceback (most recent call last):
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/discord/ext/commands/core.py", line 79, in wrapped
ret = await coro(*args, **kwargs)
File "/home/martinebots/martinebotscogs/cogs_modified/audio/audio.py", line 6455, in seek
is_alone = await self._is_alone(ctx, ctx.author)
File "/home/martinebots/martinebotscogs/cogs_modified/audio/audio.py", line 6705, in _is_alone
elif ctx.guild.get_member(member.id).voice.channel.members == 1:
AttributeError: 'NoneType' object has no attribute 'channel'

Note: Making this so i dont forget to fix it in a couple of hours