Ensure updateState() is available for software hotword.

We accidentally missed propagating this method to the interface before
the previous deadline.
Otherwise the change should be trivial and backwards compatible.

Bug: 168305377
CTS-Coverage-Bug: 183425641
Test: atest CtsVoiceInteractionTestCases
Change-Id: Ib85f5264932aeab73ff67a3371f2304d368383ae