Use updated process capability name.

Use PROCESS_CAPABILITY_POWER_RESTRICTED_NETWORK instead of
PROCESS_CAPABILITY_NETWORK so that we can eventually remove the latter.

Also make NetworkPolicyManager the source of truth for what network
process capabilities are granted based on the process state.

Bug: 135214188
Bug: 261999509
Test: atest CtsAppTestCases:ActivityManagerApi29Test
Test: atest CtsAppTestCases:ActivityManagerFgsBgStartTest
Test: atest CtsAppTestCases:ActivityManagerProcessStateTest
Test: atest CtsAppTestCases:ActivityManagerTest
Test: atest FrameworksServicesTests:ActivityManagerServiceTest
Test: atest FrameworksServicesTests:UidObserverControllerTests
Change-Id: I4bfd55aab200acba9e8911bb9d972cfad1ab7e25