DO NOT MERGE: Add unit tests to ensure VPN meteredness

These new tests ensure that VPNs report the meteredness of their
underlying networks correctly. The added test verifies VPN meteredness
for cases of metered and unmetered WiFi and Cell

Bug: 78644887
Test: This; ran on walleye-eng
Change-Id: I28bdc71a336bfd97f7908455d4781d774df44b87
(cherry picked from commit 66bc52884b1009fca7917ae89e72e8aa40f394d1)
2 files changed