Update visibility of prebuilt module api

Matches the change in r.android.com/1533059.

Bug: 174847574
Test: TARGET_BUILD_APPS=foo m nothing
Change-Id: Ic297c8225e03d52952dafa8a0fa91cca82f14bdb
1 file changed
tree: c297b5fedd9964862a972211e4acc5776cc5bea6
  1. SoongConfig.bp
  2. current/