Use mockito-extended in FrameworksNetTests

This is necessary to mock classes like BatteryStatsManager, which cannot
be used without signature permissions, and to merge the test with other
test suites that use mockito extended.

Bug: 187935317
Test: atest FrameworksNetTests
Change-Id: I5dba65d806c5d06b3ff8f633846edb911a7a44ec
9 files changed