Explicit init .rc user.

Set the user explicitly.

Bug: 276813155
Test: boot
Change-Id: I1aede5c339b0fbcf1b8676c733e08eb1a06e2285

bramble/init.bramble.rc

@@ -38,6 +38,7 @@ on property:debug.touch_sensitivity_mode=1
 service vendor.mdm_helper /vendor/bin/mdm_helper
     class core
     group system wakelock
+    user root
 
 on late-init
     chown system system /sys/devices/virtual/thermal/tz-by-name/skin-therm-monitor/trip_point_0_temp