chore: Update `with-supabase` example to use `getClaims()` (#81383)
Updates the `with-supabase` example to use the new and much faster (when
project is configured with asymmetric JWT support)
`supabase.auth.getClaims()` function instead of `getUser()`.
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Co-authored-by: Benjamin Woodruff <benjamin.woodruff@vercel.com>