WifiService: Enforce permission for enableVerboseLogging

Using enforce instead of silently ignoring calls with insufficient
permissions to let apps know that the operation failed.

Bug: 67008628
Test: Unit test
Test: Toggle verbose logging successfully from Settings.
Test: Regression tests (b/67380301) and ensured that tests can still
toggle verbose logging.
Change-Id: I15f3de0cfb8cbc68862aa30434c561d3f06a3e4b
2 files changed