Getting null in exceptions when worker failed

[Zibran1999]

Describe the bug
When a worker fails, wants to get an exception message but gets null.

Component
Fhir SyncWorker

To Reproduce
Steps to reproduce the behavior:

1. Pass wrong token while execute worker
2. run the worker
3. check Failed SyncJobStatus
4. See error

Expected behavior
Once a worker failed should get exceptions

Additional context
getting this from FhirSyncWorker:
Received result from worker Failed(exceptions=[ResourceSyncException(resourceType=List, exception=retrofit2.HttpException: HTTP 500 Server Error), ResourceSyncException(resourceType=Patient, exception=retrofit2.HttpException: HTTP 500 Server Error), ResourceSyncException(resourceType=Questionnaire, exception=retrofit2.HttpException: HTTP 500 Server Error)]) and sending output Data {StateType : com.google.android.fhir.sync.SyncJobStatus$Failed, State : {"timestamp":"2023-12-15T11:40:32.5007+05:30"}, }

while observing getting this:
Exceptions: Failed(exceptions=null)

[Zibran1999]

@jingtang10
@fredhersch
@aditya-07
@santosh-pingle

[jingtang10]

closing in favour of #1654