Changed null checks in Passpoint APIs to return non-null values

These Passpoint APIs are designated @NonNull, and so their return
values should be empty collections if a null message is received
from the AsyncChannel.

Bug: 129485601
Test: atest ClientModeImplTest
Change-Id: I1d9e864c67581fa8a4ad593b3e73b6ea6c7eb15b
2 files changed
tree: 9916b38ee137742a8fc6adb079d8fd90b7d4d4e5
  1. service/
  2. PREUPLOAD.cfg