Add permission check to setBias.

The job bias is meant to be an indication of the job type and the state
the app was in when the job was scheduled. This can only be determined
by the system and certain privileged apps. The job bias can affect some
things such as which system health factors are taken into consideration
when deciding when to run a job. Given all this, the bias should only be
set by the system or certain privileged apps. Note the required permission
on the hidden API and enforce that the calling app has the permission
when the job is scheduled.

Bug: 300477393
Test: atest CtsJobSchedulerTestCases:JobInfoTest
Test: atest CtsSyncManagerTestCases
Test: atest DownloadManagerApi28Test
Test: atest FrameworksServicesTests:BiasSchedulingTest
Change-Id: I1cb37eafc42f961dee9d2e7bc7d496a31dff31f4