Fix external_service_sync_jobs cleanup job

Created by: eseliger

This was never updated after we introduced the 'failed' state and made 'errored' transient. As a result, on dotcom we currently have 1,167,159 external_service_sync_jobs, of which.. 1,121,444 should've been deleted, only 4% of that table size are required. This'll likely also yield some nice performance gains.

Test plan

Validated that older failures I saw on my instance are now gone.