Previously: Search path would prioritise the `public` schema for searching.
Proposed change: Will now prioritise the `auth` schema first.
Reasoning: If a `public.users` table exists, calling `signUp()` will fail unless the structure matches that of `auth.users`.
Users should explicitly grant privileges to `anon`(unauthenticated clients) if they want some db objects to be publicly accessed.
This caused confusion on https://github.com/supabase/supabase/discussions/1493. So the fix is to revoke default privileges for `anon`.
