NetworkAgentConfig did not exist on Q.
Test: atest CtsNetTestCasesLatestSdk:android.net.NetworkAgentConfigTest
on Q and R devices
Bug: 150918852
Merged-In: I5414d7767c39327ff41673ff13ccd34982e10742
(cherry picked from commit d7fedf26d03759cb26a19a6558cf39189b66a681)
Change-Id: I868398148d80afb73659df4d7312f1c2e245ead9