floss: Add possibility to auto-upgrade advertisement

If we start a legacy adv set, but it's larger than legacy adv
can support, auto-upgrade and check if we can use ext adv instead.
This is a temporary workaround to mimic BlueZ behavior.

Bug: 311417973
Tag: #floss
Test: mma -j32
Test: manual with btclient
Flag: EXEMPT floss only changes
Change-Id: Ifaed769abd0cf5cd2add3fc8fdfeb4c91ad84062