Expose LRJ related JobServiceEngine APIs.

JobServiceEngine is a layer that sits under JobService that anyone can
override. Any APIs that support new JobService APIs need to be exposed
in conjunction with the JobService APIs.

Bug: 255371817
Test: atest CtsJobSchedulerTestCases
API-Coverage-Bug: 262911363
Change-Id: I7317354c4010f4c2ba12a6bbb8f930f8ce649b66