Upgrade Clerk to use Clerk Core 2

[justinadkins]

This PR updates redwood's usage of Clerk authentication to Clerk Core 2 which was introduced back in April 2024 as the new major version for Clerk.

Core 1 which is currently being used by Redwood will lose long term support in Q1 2025.

Core 2 also brings with it a lot of nice UI updates with @clerk/clerk-react@5.x seeing considerable improvements.

[justinadkins]

This is nearly ready to go, I'm running into a TS build error due to this that I could use assistance on.

[Tobbe]

Thanks for getting started on this. The types for our auth setup are pretty complicated 😰 I wrote all of that, so I'm probably bet suited to jump in to help here, but unfortunately I'm super busy with upcoming conference talks and our RSC implementation. We have a team meeting on Tuesday. I'll see if I can ask someone else to take a look!

[Tobbe]

Unfortunately no one was available to help. I'll see if I can carve out some time next week. I'm out traveling until Sunday.

[Tobbe]

@justinadkins Just wanted to let you know I/we haven't forgotten about this PR. I'll personally make sure this gets merged. But it'll be some time still before I can spend time on it. I'm doing my last talk of the year next week. So the week after that I will have time for this

(We've decided to do an overhaul of all of our auth providers, so this fits perfectly with that initiative!)