Remove use of network scores, and provider IDs in VcnNetworkProvider

This change updates the VcnNetworkProvider and associated
requestListeners to no longer use the network score and provider IDs, in
order to match the new NetworkProvider APIs.

Bug: 185204197
Test: atest FrameworksVcnTests
Change-Id: I0cabce702cfd8457fd1a152af07a847b87d67028