fix: AttributeError when fetching a message from a PartialMessageable that has a thread

[Paillat-dev]

Summary

When fetching a message that has a thread from a PartialMessageable we don't have a guild so it breaks with:

 AttributeError:'NoneType' object has no attribute 'get_thread'
[...]
# channel is a PartialMessageable
File "[...]" , line 142 , in _get_first_log_message
     return await channel.fetch_message(int(message_id_str))
File "discord/abc.py" , line 1799 , in fetch_message
     return self._state.create_message(channel=channel, data=data)
File "discord/state.py" , line 2056 , in create_message
     return Message(state=self, channel=channel, data=data)
File "discord/message.py" , line 1208 , in __init__
     self.thread = Thread(
File "discord/threads.py" , line 174 , in __init__
     self._from_data(data)
File "discord/threads.py" , line 212 , in _from_data
     if thread := self.guild.get_thread(self.id) and data.pop("_invoke_flag", False): 

Information

• 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, typehinting,
  examples, ...).

Checklist

• I have searched the open pull requests for duplicates.
• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why.
• I have updated the changelog to include these changes.
• I have read the Contributing Guidelines.
• AI Usage has been disclosed.
  • If AI has been used, I understand fully what the code does

[pycord-app]

Thanks for opening this pull request!
Please make sure you have read the Contributing Guidelines and Code of Conduct.

This pull request can be checked-out with:

git fetch origin pull/3309/head:pr-3309
git checkout pr-3309

This pull request can be installed with:

pip install git+https://github.com/Pycord-Development/pycord@refs/pull/3309/head

[Paillat-dev]

(this would have been fixed by better typing smhhhhhhh)