LDAP source sync status shows success while child tasks fail

## What

LDAP/source sync status UI lies — parent/last-successful shows success while child page tasks fail or schedules do not refresh.

## Want

- LDAP/source sync status UI lies — parent/last-successful shows success while child page tasks fail or schedules do not refresh

## Ideas this came from

- [#17216 Parent sync task shows "Successful" while child sync page tasks fail](https://github.com/goauthentik/authentik/issues/17216) — When running an LDAP sync in authentik, the parent task (Sync LDAP source) is marked as Successful, even though all of its child tasks (Sync page for LDAP sourc
- [#18180 Improve sync statuses](https://github.com/goauthentik/authentik/issues/18180) — The Authentik LDAP Source Sync fields Last successful sync and Last sync status are not getting refreshed with current task execution status and the schedules l

Start by reading the related issues #17216 and #18180, then reproduce an LDAP/source sync where child page tasks fail or schedules do not refresh. Done means the status UI reflects child-task failures and the last-successful status and schedules refresh correctly.

Written by the indexing model from the issue text.