Don't change the voice interactor setting if it's explicitly unset.

Test: manual
Test: atest CtsAssistTestCases CtsVoiceInteractionTestCases CtsVoiceSettingsTestCases
Fix: 167261484

Change-Id: Ibc2c1675f8b026f2915c3faf55e8ff3c52e1ee32
Merged-In: Ibc2c1675f8b026f2915c3faf55e8ff3c52e1ee32
1 file changed