fix: add BanEntry to __all__ exports in guild.py

[Lumabots]

Summary

So just adding the banentry class so we can use it from typehint since its also returned in some function
(also make sens because its import in some file to have it in the all (if i do get the point of the all)

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.