IWLAN handover optimization

Ignored preference change update from access network
manager if handover is ongoing, and then perform
handover evaluation again after handover completes to
prevent out-of-sync with QNS.

Also fixed the debug messages for setup data call
and deactivate data call.

Fix: 224743569
Test: Manual + atest DataNetworkControllerTest

Change-Id: Ic6ba2d662ca23b0c0f5b618ac7f04c546b49ff50