Refactor payments

## Basic Information
- Payment form in `create-account` (uses raw OnlinePaymentForm)
- Payment form in `@membership` (uses PaymentFormWrapper)
- Payment form in `dashboard (root)` (uses PaymentFormWrapper)

1. Directly call update role on backend in payment procedure
2. Remove handleAfterPayment usage for wrappers
3. Simplify create-account afterPayment handler to just redirect to dashboard
4. Add proper error messages to client (onError passes down the trpc error message)
5. Make a loading.tsx for `dashboard (root)` while you're at it

## Other Information
**[Are there any additional information that we should know about?]**