Opt out of small battery values for Wear in DeviceIdleController

Before this change, there are some Idle related values that are applied
to small battery devices, without considering those devices' XML config
overlay. This change opts Wear out of the small battery values, so that
Wear devices can freely configure their Idle related constants via the
config overlay.

Bug: 431863848
Test: atest DeviceIdleControllerTest
Flag: EXEMPT trivial refactor
Change-Id: I04d3880e92dd1784a57289b58c0189dd4ec2af6b