fix(audit_logs)!: channel_id can be None due AutoMod blocking nickname changes

[kingmigdor]

Summary

Fixes #1038. There's a possibility that channel_id for being None when a nickname change was blocked by AutoMod and this has been logged in the AutoMod log channel.
Also removes some repetition in audit_logs.py

Testing code: https://paste.nextcord.dev/?id=1682809496392755

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
  • I have run task pyright and fixed the relevant issues.
• 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, ...)

[Miolus]

This is needed since it also leads to hard crashes once an audit_log_entry_create event fires without a channel id.