Avoid calling postOneTimeCheckIdleStates on boot.

When we used Settings flags, we didn't call postOneTimeCheckIdleStates()
on boot. Remove it from the boot path when using DeviceConfig to avoid
unnecessary work.

Bug: 172193270
Test: atest AppStandbyControllerTests
Change-Id: I6b05eb4a6565e49c051d3a2ca41986d873acf4e8
1 file changed