Fix AIDL VHAL metadata extraction script

Add capability to process values from imports.
Update json metadata file with new data.

Testing:
1. cd hardware/interfaces/automotive/vehicle/aidl/emu_metadata
2. ./generate_emulator_metadata.py ../../aidl_property/android/hardware/automotive/vehicle out.json

Bug: 317529575
Test: manual
Change-Id: I315f1f75c2372796bde3bdacd39246344579c002
2 files changed