[Sb refactor] WIP - InternetTileViewModel

This CL represents an implementation an InternetTileViewModel, which can
correctly calculate a state object (`InternetTileModel`) to fund a
repository-backed internet QS tile.

The `InternetTileBinder` will attach this model flow to the consumer
provided by the QS tile itself, which can then update its own itnernal
QS state object in its own handler.

Still WIP - needs a few more tests and an `areNetworksAvailable` flow
from the wifi stack. These will be implemented in a follow-up

Test: InternetTileViewModelTest
Bug: 291321279
Change-Id: Id2bd19da17e124cdf3b7c937f0fd28e158910960