[Streams] Switch to Twitch's newer follower endpoint

[karlsbjorn]

Description of the changes

Switches to the newer non-deprecated follower endpoint for Twitch since the one we're using now is being decommissioned.
Closes #6246

Have the changes in this PR been tested?

Yes, with [p]twitchstream

[palmtree5]

This solution is actually not enough as the way we authenticate with Twitch's API at the moment results in an app access token, which is not enough to use /helix/channels/followers as that endpoint requires a user access token that has the moderator:read:followers scope and given we only use this information to get a follower count, it might be better to just remove it for the moment, or replace it with some other useful piece of information

[karlsbjorn]

Not having the scope should be fine for our use case here, no? This is from the Twitch docs here: https://dev.twitch.tv/docs/api/reference/#get-channel-followers

Works fine in my testing. I definitely don't have that scope:

[palmtree5]

ya know, I think I read that line once, months ago when the change was first announced, but then when I read it when writing that review I missed that line lmao. Yeah, this should be perfect then

hurr durr why don't I actually read every word of the API documentation lmao 🤪