IWLAN handover fix

Explicitly tear down the data connection on the
source transort when handover failed with non-fallback
fail cause. Explicitly tearing it down without waiting
for connectivity service calling unwanted (which will not
happen because the network request is not removed).

Fix: 155079915
Test: Telephony sanity tests
Change-Id: I02f22d8d11661a7e938177c3ca4968202fe00e44