Remove apex_available on libandroid_runtime_vm_headers

Dependency of media APEXes on libbinder has been
cleaned up. Hence, there's no need to make
libandroid_runtime_vm_headers apex_available to
these APEXes.

Fixes: 193742372
Test: TH

Change-Id: Ide613376b94e1680ab7e26ef5cb975a80c44fb01