feat: add missing args to Guild.create_forum_post

[AstreaTSS]

Pull Request Type

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

Description

This adds two new arguments that were missing from create_forum_post (but are documented in the Discord API docs) - default_reaction_emoji and available_tags. This also adds a ton of logic to make that possible and seamless, and also to fill in the gaps that were created from the absence of these two.

Changes

• Added default_reaction_emoji and available_tags to Guild.create_forum_post.
  • These were made to be as lenient and support the most formats possible - as such, the code is slightly unclean.
• Created DefaultReaction and add it to GuildForum.
  • This is currently barebones, not having helper methods due to the complexity that brings.
• Create a locally-friendly classmethod for creating ThreadTags for usage for create_forum_post.
  • This requires a few hacks and isn't actually a real object, but it becomes a valid payload all the same.
• Made a processing method for ThreadTag and DefaultReaction.

Related Issues

Test Scenarios

One of many ways of using this new feature is:

await guild.create_forum_channel(
    name="test",
    default_reaction_emoji="🦀",
    available_tags=interactions.ThreadTag.create("test", moderated=True, emoji="👍"),
)

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