Message.editable doesn't work in threads

[Pjiesco]

Issue description

Steps to reproduce:

1. register event for the messageCreate event.
2. Send a message in a thread
3. See how it fails.

Possible cause (I'm almost certain that this is the cause):
It tries to run this.channel?.viewable on the thread channel but thread channels do not have a viewable property resulting in null/false

  get editable() {
    return Boolean(this.author.id === this.client.user.id && !this.deleted && (!this.guild || this.channel?.viewable));
  }

Source

Code sample

client.on('messageCreate', (message) => {
    if (message.channel.type == ChannelType.GuildPublicThread) {
        if (message.editable) {
            message.edit("Edited message");
        }
    }
})

discord.js version

13.3.1

Node.js version

16.6.1

Operating system

Windows

Priority this issue should have

Low (slightly annoying)

Which partials do you have configured?

No Partials

Which gateway intents are you subscribing to?

GUILDS, GUILD_MEMBERS, GUILD_BANS, GUILD_MESSAGES, GUILD_MESSAGE_REACTIONS, GUILD_MESSAGE_TYPING

I have tested this issue on a development release

No response

[Jiralite]

Possible cause (I'm almost certain that this is the cause):
It tries to run this.channel?.viewable on the thread channel but thread channels do not have a viewable property resulting in null/false

Yep, that'll be the cause. Thread channels don't have this property, so this becomes undefined, so the expression becomes true && true && (false || undefined) which gets converted to false.