Updates to ConnectivityService so that the set OEM network preference per app APIs can be tested via CTS. Bug: 176496580 Bug: 176494815 Test: atest FrameworksNetTests atest FrameworksNetIntegrationTests atest CtsNetTestCasesLatestSdk Original-Change: https://android-review.googlesource.com/1723050 Merged-In: I5a47dcece31749293f080af060218d827082eb67 Change-Id: I5a47dcece31749293f080af060218d827082eb67