fix: unnecessary set default_transaction_isolation

src/PostgREST/Config/Database.hs

@@ -154,7 +154,7 @@ queryRoleSettings prepared =
       select
         kv.rolname,
         i.value as iso_lvl,
-        array_agg(row(kv.key, kv.value)) filter (where key <> 'default_transation_isolation') as role_settings
+        coalesce(array_agg(row(kv.key, kv.value)) filter (where key <> 'default_transaction_isolation'), '{}') as role_settings
       from kv_settings kv
       join pg_settings ps on ps.name = kv.key and ps.context = 'user'
       left join iso_setting i on i.rolname = kv.rolname