Switch to a SystemApi to get service info.

The mechanism we were using was through a hidden API. Switching to a
SystemApi as part of the mainline effort.

Bug: 142281756
Test: atest com.android.server.job.controllers.ConnectivityControllerTest
Test: atest com.android.server.job.controllers.JobStatusTest
Test: atest com.android.server.job.controllers.QuotaControllerTest
Test: atest com.android.server.job.JobSchedulerServiceTest
Test: atest com.android.server.job.JobStoreTest
Test: atest CtsJobSchedulerTestCases
Change-Id: Idac1833329b81a7f7d986767f241f27a0a1cf6ca