refactor: remove deprecated Message#deleted accesses

[Nytelife26]

In discordjs/discord.js#7092, Message#deleted and the same property on other structures (but we only use the ones for Message) were deprecated. There are two accesses for this property, both in the message utils.

Initially I'd suggest removing the check and handling it caller-side since the current proposed solutions for checking if a message is deleted or not involve cacheing in a WeakSet, but the function is called in many places and that would add a lot of code. Therefore, I do not have a good solution to propose, and this issue is just to bring it to attention.

[favna]

Yeah I'm aware. I get notified everytime I restart Skyra for an update through the logging. Good to officially list it here though.

[Nytelife26]

Yeah I'm aware. I get notified everytime I restart Skyra for an update through the logging. Good to officially list it here though.

I knew you would be, but tracking issues are always good. I'm hoping there'll be a good solution without too much boilerplate.

[kyranet]

This has been fixed in the v14 rewrite long ago.