[Studio] Functions can be shown as revoked while remaining executable through PUBLIC

# Bug report - [x] I confirm this is a bug with Supabase, not with my own application. - [x] I confirm I have searched the [Docs](https://docs.supabase.com), GitHub [Discussions](https://github.com/supabase/supabase/discussions), and [Discord](https://discord.supabase.com). ## Describe the bug Studio's **Exposed functions** state can report a function as `revoked` even though `anon` can still execute it through PostgreSQL's `PUBLIC EXECUTE` privilege. I reproduced the mismatch end-to-end with PostgREST: ```text Studio access state: anon_execute = false status = revoked PostgreSQL effective privilege: has_function_privilege('anon', function_oid, 'EXECUTE') = true PostgREST: POST /rest/v1/rpc/<function> → HTTP 200 → current_user = anon ``` So the access state shown by Studio can disagree with the privilege PostgreSQL/PostgREST actually enforces. ## To Reproduce This reproduces with the current default-privilege behavior used by Studio. 1. Create a function without an explicit ACL: ```sql create function public.studio_privilege_repro() returns json language sql as $$ select json_build_object( 'ok', true, 'current_user', current_user ); $$; ``` 2. Check the effective privilege: ```sql select has_function_privilege( 'anon', 'public.studio_privilege_repro()', 'EXECUTE' ); ``` This returns `true`. `proacl` is `NULL`, so PostgreSQL falls back to its built-in function ACL, which grants `EXECUTE` to `PUBLIC`. 3. Check Studio's Exposed functions state for the same function. The query reports: ```text anon_execute = false auth_execute = false srv_execute = false status = revoked ``` 4. Call the function through PostgREST as the anonymous role: ```text POST /rest/v1/rpc/studio_privilege_repro ``` Result: ```text HTTP 200 { "ok": true, "current_user": "anon" } ``` The RPC also appears in PostgREST's OpenAPI output. ## Expected behavior Studio's **Exposed functions** state should reflect whether the Data API roles can effectively execute a functio…