Skip wifi stats test if link layer stats is not supported

Wifi link layer is an optional feature so this test will be
failed on wifi stats check if a device does not support it.
Add a check to know if the  device supports wifi link layer
stats and skip it if it is not supported.

Ignore-AOSP-First: Needs cherry-picks
Bug: 195518957
Test: CtsNetTestCases:BatteryStatsManagerTest
Change-Id: I592dd5f1d6e13b020beadb11b9d913857a82e524