[RAM] Add new attribute snoozeEndTime to alert saved objects (#125992)

* Add snooze_end_time property

* Switch property name to camelcase and add to types

* Switch to strict_date_time

* Remove number from types

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/alerting/server/saved_objects/mappings.json

@@ -155,6 +155,10 @@
             }
           }
         }
+      },
+      "snoozeEndTime": {
+        "type": "date",
+        "format": "strict_date_time"
       }
     }
   }

x-pack/plugins/alerting/server/types.ts

@@ -250,6 +250,7 @@ export interface RawRule extends SavedObjectAttributes {
   meta?: AlertMeta;
   executionStatus: RawRuleExecutionStatus;
   monitoring?: RuleMonitoring;
+  snoozeEndTime?: string;
 }
 
 export type AlertInfoParams = Pick<