DeviceStateMonitor: Rename indication filter "turn on" into "enable"

Then naming of turning on filters has ambiguity if it's enabling
filter or enabling the signal (which means disabling filter).

Bug: 151462907
Test: atest DeviceStateMonitorTest
Merged-In: I0b43b0c2f346fb54cde806754db21efb21d4f624
Change-Id: I0b43b0c2f346fb54cde806754db21efb21d4f624
(cherry picked from commit 77631e9d)