Add connectivity pre-check for net permission cts tests

The net permission cts tests require an available network to run.
Therefore, a connectivity pre-check should be added to ensure
that there is an active network before running the tests.

Test: atest CtsNetTestCasesUpdateStatsPermission \
      CtsNetTestCasesInternetPermission
Change-Id: I1c7fb43bb009eb0fd2570bc40a14e55f5ebd2d8b
4 files changed