Fix violation of least privilege principle

The confirmationui HAL does not need to run as user system.

Bug: 63928580
Test: All required services boot and can access what they need
Change-Id: Ic2d6edabf8cca8384a7e0ce49dfc5445a6ec1658
diff --git a/confirmationui/1.0/default/android.hardware.confirmationui@1.0-service.rc b/confirmationui/1.0/default/android.hardware.confirmationui@1.0-service.rc
index a278028..c04e55e 100644
--- a/confirmationui/1.0/default/android.hardware.confirmationui@1.0-service.rc
+++ b/confirmationui/1.0/default/android.hardware.confirmationui@1.0-service.rc
@@ -1,4 +1,4 @@
 service vendor.confirmationui-1-0 /vendor/bin/hw/android.hardware.confirmationui@1.0-service
     class hal
-    user system
-    group system drmrpc
+    user nobody
+    group drmrpc