Check preferred transport from the result received

AccessNetworksManager can revert the preferred transport change
before the client handles the first change,
and AccessNetworksManager#getPreferredTransport() returns the last state.
So, the client can miss the first change.
Client should get the preferred transport from the result received by
itself instead of the AccessNetworksManager#getPreferredTransport().

Bug: 266189145
Test: atest DomainSelectionConnectionTest
Change-Id: I208a396b3c4484e91ce268e359f4783f0f3ddf63