Add VPN UT and CTS into presubmit

Changes in VpnManagerService does not trigger VPN UT and CTS
in presubmit. It will introduce unexpected test failure if
the commit is not well-tested.

Bug: 286302640
Test: m
Change-Id: Ia608a96ff721239870b2334b7d9f63f54c4300ea
1 file changed