Add wireless/device/mitigate_threshold to control Dream Defend from GoogleBattery am: df5f6ee522 am: 833a62da50 am: 7bf38352c7

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

Change-Id: If8371c062236c39ac954e0ff011fdf279f7f3361