Add Users column to SAPETDAlerts_CL KQL validation schema

The analytic rules now mv-expand Users for email extraction,
but the KQL validation custom table definition was missing this column.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: MartinPankraz

.script/tests/KqlvalidationsTests/CustomTables/SAPETDAlerts_CL.json

@@ -52,6 +52,10 @@
       {
         "name": "NormalizedTriggeringEvents",
         "type": "dynamic"
+      },
+      {
+        "name": "Users",
+        "type": "dynamic"
       }
     ]
 }