feat: ✨ Add MediaChannel and fix ForumChannel flags

[Paillat-dev]

Summary

Fix #2637
Fix #2640

Information

• This PR fixes two issues.
• 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.

[Lulalaby]

I'm not entirely sure but afaik I the channel class you also have a model for the base type which has type: literal channel type blah. Is that perhaps missing?

[Paillat-dev]

I'm not entirely sure but afaik I the channel class you also have a model for the base type which has type: literal channel type blah. Is that perhaps missing?

type is present as a property in some channel classes but not all, for example it is not in TextChannel (which I found weird tbh) but is in others. I added it to ForumChannel and MediaChannel, even tough it works without because it is already implemented in _TextChannel as follows:

    @property
    def type(self) -> ChannelType:
        """The channel's Discord type."""
        return try_enum(ChannelType, self._type)

[Dorukyum]

It's redundant if the classes inherit from _TextChannel.

[Paillat-dev]

Undid it then

.