Include extra licenses in vendor image NOTICE file

If building with a vendor image, ensure that the licenses from
extra partitions are included in the vendor NOTICE file (possibly in
addition to having them in the system NOTICE file) since they could come
from disperate source trees. This change does not affect existing NOTICE
files outside of the system partition. (e.g. product and system_ext).

Bug: 134679603
Test: Built a vendor image enabled target and ensured the notices were in the
proper file
Change-Id: Ib17c7d7f84805734de09e686a4835b9b680b4192