Use the new NetworkStackConnector constructor

The constructor was changed to allow for unit tests.

Bug: 137328719
Test: atest FrameworksNetIntegrationTests
Original-Change: https://android-review.googlesource.com/1295360
Merged-In: I46f247268310e12d420531745a22e93cf3550e89
Change-Id: I46f247268310e12d420531745a22e93cf3550e89