Verify private DNS change applied to all Networks

Test may be flaky because the target network did not apply the
private DNS setting change because test assumes setting applied
successfuly by receiveing any success from link properties
change. The test failed because the target network did not apply
the change. Test should wait for setting to be applied to all
networks since the private DNS setting change will be applied
one by one for each Network

Fix: 279051721
Test: atest com.android.cts.net.HostsideVpnTests
Change-Id: I649c2d573a245f15b7749c3b0ac824d2f846873c
1 file changed