[Bug Fix] Custom SimpleJob Id ignored

[MattFromRVA]

Fixes #2473

[MattFromRVA]

@dotnet-policy-service agree

[AndreyAkinshin]

@MattFromRVA thanks for the PR! Indeed, it's an unpleasant bug and it's nice to have it fixed.

P.S. A side note: the whole Characteristic* infrastructure is a huge technical debt introduced in 2016. Back in those times, I had no idea about the actual feature set we needed, so I tried to design a flexible and generic approach. Unfortunately, the API turned out to be over-complicated, which is quite challenging to maintain. In my backlog, I have a long-living task of burning Characteristic* and redesigning the Job API from scratch targeting the current set of features. However, this task is not product-critical (the current system just works most of the time), so it's always deprioritized (no ETA for now).

[MattFromRVA]

@AndreyAkinshin no problem! Thanks for the additional history. When that backlog item becomes a priority I would be happy to help contribute.