gs_watchdogd: add shutdown critical option

Watchdogd should be alive to complete shutdown
safely. This also aligns the behavior with previous
watchdogd.

Bug: 267080705
Test: boot
Change-Id: Iad85a0d730d032ae57530e0aa6965e2123488b2f
Signed-off-by: Martin Liu <liumartin@google.com>
diff --git a/gs_watchdogd/init.gs_watchdogd.rc b/gs_watchdogd/init.gs_watchdogd.rc
index 450daa1..f58ce50 100644
--- a/gs_watchdogd/init.gs_watchdogd.rc
+++ b/gs_watchdogd/init.gs_watchdogd.rc
@@ -3,6 +3,7 @@
     class core
     oneshot
     seclabel u:r:gs_watchdogd:s0
+    shutdown critical
 
 on property:vendor.all.devices.ready=1
     start gs_watchdogd