fix: Edit both current user @me and by id if applicable

[Paillat-dev]

Summary

Currently, passing both avatar and roles for e.g. would fail at setting the guild-specific avatar.

I am not sure if this is the best fix, specifically since for e.g. nick can both be set with Modify Guild Member and Modify Current Member (with manage_nicknames vs change_nickname). Maybe having manage_nicknames also implicitly allows change_nickname, that would make sense but idk if it is being authorized on an API level.

Maybe we should create a different Guild.modify_current_member (or other name), and deprecate these in order to be closer to the API and have better and clearer logic here ?

This bug was identified by Anthropic Fable 5, then verified and patched by me (pending discussion).

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.
• AI Usage has been disclosed.
  • If AI has been used, I understand fully what the code does

[pycord-app]

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This pull request can be checked-out with:

git fetch origin pull/3258/head:pr-3258
git checkout pr-3258

This pull request can be installed with:

pip install git+https://github.com/Pycord-Development/pycord@refs/pull/3258/head

[Lulalaby]

Yes we should aim for a current member function. It makes the most sense