feat/fix💥: adjust and fix various issues with scheduled events

[AstreaTSS]

Pull Request Type

• Feature addition
• Bugfix
• Documentation update
• Code refactor
• Tests improvement
• CI/CD pipeline enhancement
• Other: [Replace with a description]

Description

This PR improves using scheduled events in the library by fixing longstanding issues related to it and its events. In particular, this adds a proper method for fetching scheduled events in the cache, adds a get event for scheduled events for guilds, and fixes GuildScheduledEventUserAdd/Remove since those were utterly broken.

Note: this technically is breaking, and so should have some eyes on it. However, GuildScheduledEventUserAdd/Remove is so broken and unusable in its current state to the point where you would have to use a raw event to get any useful information most of the time. I understand that violates our versioning standards, but I legitimately think this is such an extreme case that it should be considered.

Changes

• 💥 Fix GuildScheduledEventUserAdd/Remove by properly passing the IDs instead of the objects of the events.
• Fix the get scheduled event HTTP method to properly pass in with_user_count.
• Add in fetch_scheduled_event to SmartCache.
  • The Guild variant now uses the above method, using the cache properly.
• Add in get_scheduled_event to Guild.
• Properly typehint user_count in ScheduledEvent.

Related Issues

Test Scenarios

Python Compatibility

• I've ensured my code works on Python 3.10.x
• I've ensured my code works on Python 3.11.x

Checklist

• I've run the pre-commit code linter over all edited files
• I've tested my changes on supported Python versions
• I've added tests for my code, if applicable
• I've updated / added documentation, where applicable

[i0bs]

I cannot access Discord, but I believe decision making of placing this on hold up to @LordOfPolls since it's an obvious breaking change.

[LordOfPolls]

Merging as non breaking - you cant break the api for something that never worked to start with