floss: Align included service handling with Android GattService

This patch aligns behavior between floss service_added_cb and
Android onServiceAdded by skipping included services.

Bug: 318461736
Tag: #floss
Test: m -j
Flag: EXEMPT, floss only change
Change-Id: Ib78192bfc5c5b53d4d952218f6f1697e639d425f