Add wireless/device/mitigate_threshold to control Dream Defend from GoogleBattery am: df5f6ee522 am: 833a62da50

Original change: https://android-review.googlesource.com/c/platform/hardware/google/pixel-sepolicy/+/1674303

Change-Id: I682cd76412b88926ea58dae9b71db9cd2622d03d