Drop androidx libraries from baselineApexAvailable

These are not needed in this map since the Android.bp files for these
modules are created by pom2bp script
which explicitly set apex_available as ['//apex_available:apex',
'//apex_available:platform'].

Bug: 281077552
Test: m nothing
Change-Id: I53bb9a104b1e7a2535fe568e27431b1a48a885e3