Make most of NetworkAgent @SystemApi.

Bug: 138306002
Bug: 139268426
Test: atest FrameworksNetTests FrameworksWifiTests FrameworksTelephonyTests
Test: atest android.net.cts.ConnectivityManagerTest
Change-Id: I856f01f02c35c2f6a886d8b98039e5dfbc48148b
Merged-In: I856f01f02c35c2f6a886d8b98039e5dfbc48148b
(cherry picked from commit 10a12966c27d1dfe33c2545b8763bde0118dfe42)
1 file changed
tree: cc7e83d892c7dadb3bf814ab441ad879a7e098d2
  1. core/
  2. services/
  3. tests/