apex: validate vintf fragments in vendor APEX

In Make, vintf fragments are checked with assemble_vintf. Since vendor
APEXes can have vintf fragments, perform the same check with vintf
fragments in APEX.

Bug: 299034304
Test: m test.bad2.com.android.hardware.wifi
  (should fail if its module type is `apex`)
Change-Id: I2f9ed50066b9b499b3562bfa51214c1e375d5747