Fix exception when checking owner status and guild is not present

[apdastous]

Just found this repo recently, love it!

I've been testing my bot and ran into an issue where owner only commands were failing in DMs. I used the testcommand and get this traceback due to context.guild not containing expected attributes. PR is a simple fix for this issue.

  File "/home/apd/projects/mrvn-apexlegends-discord-bot/venv/lib/python3.10/site-packages/discord/client.py", line 409, in _run_event
    await coro(*args, **kwargs)
  File "/home/apd/projects/mrvn-apexlegends-discord-bot/bot.py", line 239, in on_command_error
    f"{context.author} (ID: {context.author.id}) tried to execute an owner only command in the guild {context.guild.name} (ID: {context.guild.id}), but the user is not an owner of the bot.")
AttributeError: 'NoneType' object has no attribute 'name'

[kkrypt0nn]

Hey there!

Thanks for noting that out and for wanting to fix it, though you are not following the Contributing Guidelines.

Please follow these guidelines and update your contribution accordingly, thanks in advance.