Subscribe to light sensor if idle screen refreshrate is defined

This addresses the issue where DisplayModeDirector would only subscribe
to the light sensor if low or high blocking zones are defined. However,
with the recent introduction of idle screen refresh rate timer, we
should also subscribe to the Light Sensor via DisplayModeDirector if idle screen refresh rate config is present.

Bug: 358019330
Test: Manual
Test: atest DisplayModeDirectorTest
Flag: com.android.server.display.feature.flags.idle_screen_config_in_subscribing_light_sensor
Change-Id: I8437829fb0d3d46ecc7a6ec9afd4071cfc27e1a5