Explicitly set user root for the gs_watchdogd service. am: f25cb6895f

Original change: https://android-review.googlesource.com/c/device/google/gs-common/+/3250951

Change-Id: I58b8abe45d82b6ea620d6e623c4716785a992c76
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>