Migrate /unban command to Helix API

[jupjohn]

As part of Twitch's announced deprecation of IRC-based commands (see here for more info, the /unban command needs to be migrated to use the relevant Helix API endpoint.

Helix API reference: https://dev.twitch.tv/docs/api/reference#unban-user

Split from #3956

[aidenwallis]

I can take this

[Felanbird]

Discussed in chat:

[2022-10-1 17:41:23] #pajlada mm2pl: Aiden: does your /unban, /untimeout PR somehow differenciate between bans 
and timeouts? If a user is banned, does /untimeout unban them? pajaThink
[2022-10-1 18:02:07] #pajlada felanbird: @Mm2PL it does not differentiate, untimeout does unban but it works 
like that in IRC as well
[2022-10-1 18:02:35] #pajlada mm2pl: wait since when does untimeout unban FeelsNotSureLady
[2022-10-1 18:02:40] #pajlada mm2pl: it didn't use to be the case FeelsNotSureLady
[2022-10-1 18:03:15] #pajlada felanbird: @Mm2PL no idea but i executed it with and without the PR and it unbanned
[2022-10-1 18:03:23] #pajlada mm2pl: ic

[2022-10-1 18:04:38] #pajlada felanbird: i wonder if handling it the old way is more correct tho mm2pl
[2022-10-1 18:05:00] #pajlada felanbird: i think of nymn's chat where some idiot would tell u to untimeout 
someone and u'd accidentally bypass a ban u didn't know about doing so
[2022-10-1 18:05:57] #pajlada mm2pl: idk i liked the idea of bans and timeouts being separate, 
for example paid untimeout could unban, so could a mod by accident Hmmm
[2022-10-1 18:06:11] #pajlada felanbird: indeed

Is there any world where we adapt our implementation to prevent untimeout from removing a ban?

[pajlada]

I'd say so yeah, if it's possible. Could be made as a new github issue as an enhancement

[Felanbird]

if it's possible.

That's the tricky part, I'm unsure 🤔