Fixed that WiFi calling icon not shown

The logic of isAnyApnOnIwlan only checks "current transport", while
in the new data stack, "current transport" concept is abandoned.
Only "preferred transport" is maintained.

Used "preferred transport" to determine if any APN is on IWLAN
when new data stack is running.

Also migrated the unit tests to use Google common truth.

Fix: 217981412
Test: Manual
Change-Id: I973888430d382cafc8c4396b62c06235eaecbd49