fix(express-context): read auth_settings_table_name directly

[pyramation]

Summary

Removes the transitional coalesce shim in the auth-settings loader now that constructive-db has renamed the column everywhere (constructive-db#2194 merged).

The column sessions_module.auth_settings_table was renamed to auth_settings_table_name to avoid a PostGraphile inflection collision with auth_settings_table_id. #1376 added a compatibility read that tolerated both names:

coalesce(to_jsonb(sm) ->> 'auth_settings_table_name',
         to_jsonb(sm) ->> 'auth_settings_table') AS table_name

Since every metaschema now has the renamed column, this reverts to a direct read:

SELECT s.schema_name, sm.auth_settings_table_name AS table_name
FROM metaschema_modules_public.sessions_module sm
JOIN metaschema_public.schema s ON s.id = sm.schema_id
LIMIT 1

Link to Devin session: https://app.devin.ai/sessions/b0cb3356cae14cc28fa469b4f8fd3e1d
Requested by: @pyramation

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