Add new interaction channel attribute

[davfsa]

Checklist

• I have run nox and all the pipelines have passed.
• I have made unittests according to the code I have added/modified/deleted.

[davfsa]

I am not sure whether to get rid of BaseInteraction.get_channel and BaseInteraction.fetch_channel, as they are a bit replaced here. The only difference is the more concrete type.

I would get rid of them, but I would like more feedback :)

[FasterSpeeding]

the channel objects here include a lot more fields than just the partial channel's fields

e.g.

{
    "type": 0,
    "topic": null,
    "theme_color": null,
    "rate_limit_per_user": 0,
    "position": 20,
    "permissions": "140737488355327",
    "parent_id": "561885448721399808",
    "nsfw": false,
    "name": "dwads",
    "last_message_id": "1114922806820479057",
    "id": "717586538925523004",
    "icon_emoji": {
        "name": "\ud83e\udd16",
        "id": null
    },
    "guild_id": "561884984214814744",
    "flags": 0,
    "default_auto_archive_duration": 60
}

{
    "type": 1,
    "last_message_id": "1096465893028003910",
    "id": "463185043796262922",
    "flags": 0
}

[FasterSpeeding]

This was also mentioned in the PR which documented this field discord/discord-api-docs#6051 (comment), just another case of Discord having shit docs tbh