[Bug]: SimpleFIN Cloudflare Block is not handled gracefully

### What happened?

Was linking bank accounts several times, leading to a Cloudflare block on Simplefin. Since the credentials box popped up, I unnecessarily reset my credentials for SimpleFIN. Now I get to set all my bank accounts back up again when the link is restored.

### How can we reproduce the issue?

1. Create a SimpleFIN account and link a Bank Account and create an App Connection
2. Create an Account in Actual
3. In the Meatball menu, click Link Account
4. Click Link Account with SimpleFin
5. Provide the App Credentials created in step 1
5. Keep using Link Bank/syncing/etc. until SimpleFIN temporarily bans requests from the backend to their API, resulting in syncs failing
6. Observe Cloudflare Rate-Limit HTML in Actual Server logs.
7. Create a new Account
8. In the Meatball menu, click Link Account
9. Click Link Account with SimpleFin

Expected: Warning displayed that SimpleFin is unavailable/rate limit
Actual: "Set Up SimpleFIN" modal is displayed

### Where are you hosting Actual?

Fly.io

### What browsers are you seeing the problem on?

Chrome

### Operating System

Windows 11