Set apex_available property

The marked library(ies) were available to the adbd APEX via the
hand-written whitelist in build/soong/apex/apex.go. Trying to remove the
whitelist by adding apex_available property to the Android.bp of the
libraries.

Exempt-From-Owner-Approval: already +2'ed by the owner (enh)

Bug: 150999716
Bug: 151398197
Test: m
Change-Id: I8b572e3c4e76bd10c0443a6c08b72e9519243ab5