Fix the vendor api level

The test vendor api level must read both device api level
(ro.product.first_api_level) and the board api level
(ro.board.first_api_level) and use the minimum of these values.

Bug: 202919753
Bug: 200133996
Test: atest vts_treble_vintf_vendor_test
Change-Id: I4fee735996410e176d0b7634fc65ae8e793698c5
2 files changed