Increase test coverage for VPN info sent to NetworkStatsService.

Bug: 172870110
Test: test-only change
Change-Id: I3711b362f31cb92b759e9f5c9d244fb88d9bd5e7
Merged-In: I3711b362f31cb92b759e9f5c9d244fb88d9bd5e7
(cherry picked from commit d10299582ae9965c0ff70b5fceb4ce8ee591734e)
1 file changed