fix: suppress the Warnings on missing properties (#1707)

Update the Warning alarm suppressions to ignore the missing
properties in the `class-wp-rest-templates-controller`.

These are occurring when specific posts are saved and
do not have a have user or data impact.

infrastructure/terragrunt/aws/alarms/locals.tf

@@ -35,6 +35,7 @@ locals {
     "warning",
   ]
   wordpress_warnings_skip = [
+    "Attempt to read property*class-wp-rest-templates-controller.php",
     "Undefined array key*c3-cloudfront-clear-cache",
     "/usr/src/wordpress/wp-content/languages",
     "chmod()",