Count proxy jobs toward scheduling limit.

Limit schedule calls for persisted proxy jobs.

Bug: 377912323
Bug: 299930087
Test: atest FrameworksMockingServicesTests:com.android.server.job.JobSchedulerServiceTest
Flag: com.android.server.job.enforce_schedule_limit_to_proxy_jobs
Change-Id: I4ebcdd6ee299347d7d5cf6e228ba441b73db7481