Possible incorrect granted permission in example RLS policy

[brandonw4]

For the RLS example policy "Allow authenticated group members with any role to read groups"
Currently the permissive check is for all instead of for select.

supabase-tenant-rbac/examples/policies/role_centric.sql

Lines 43 to 49 in fda1410

	-- Allow authenticated group members with any role to read groups
	create policy "Members can read"
	on "public"."groups"
	as permissive
	for all
	to authenticated
	using (user_is_group_member(id));