Use flag to control the restart period value.

Bug: 224618257
Test: adb shell cmd device_config get/put voice_interaction \
restart_period_in_seconds works fine
Test: the value is expected by command: adb shell dumpsys \
voiceinteraction | grep RESTART_PERIOD_SECONDS

Change-Id: Icd8d19c2a482d0d6b9bf0432e2176ca10f3bd2eb
Merged-In: Icd8d19c2a482d0d6b9bf0432e2176ca10f3bd2eb
(cherry picked from commit 46e69448)