Added coverage tests and fixed 2 additional issues:

- Check if keyguard is locked before disabling USB upon enablement of feature.
- Fixed issue with UsbDataStatus value being treated as IntDef enum vs bitmask

Bug: 419815826
Test: manual testing, atest FrameworksMockingServicesTests
Flag: android.security.aapm_feature_usb_data_protection
Change-Id: I34f5fc7b30efa2e963da10ef1d3f0441da559464