Fix circular import

[1oonie]

Summary

This PR fixes a circular import issue that came from importing _BaseCommand from the _types.py file.

For reference, this is what used to happen:

Python 3.9.6 (default, Aug 23 2021, 19:43:03) 
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import discord.bot
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/esmecat/pycord/discord/__init__.py", line 62, in <module>
    from .bot import *
  File "/home/esmecat/pycord/discord/bot.py", line 28, in <module>
    from .ext.commands._types import _BaseCommand
  File "/home/esmecat/pycord/discord/ext/commands/__init__.py", line 11, in <module>
    from .bot import *
  File "/home/esmecat/pycord/discord/ext/commands/bot.py", line 1036, in <module>
    class Bot(BotBase, discord.Bot):
AttributeError: partially initialized module 'discord' has no attribute 'Bot' (most likely due to a circular import)

I am not sure why this import was here in the first place (so I could be wrong in removing it) so please point this out to me if I am incorrect.

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[Dorukyum]

This doesn't solve the issue as it is at the moment.

[1oonie]

It seemed to solve it for me but I'll close this anyways.

[Dorukyum]

My bad, I tested it incorrectly.