Fix NPE when pfd is not present

When a pfd is returned from VIS, we should check if pfd is null or not
to avod NPE. If the pfd is null, we need to throw a IOException as the
javadoc alludes.

Bug: 315207356
Test: atest CtsVoiceInteractionTestCases
Flag: N/A
Change-Id: Ibaed9970c1ea841432361254468ac87c703a84f2