Add CreateAdminNPC no-op comparison fixture

hwe/compare/monthly_event_trace.php

@@ -184,6 +184,7 @@ function comparisonMonthlyEventTraceMain(): void
             'UpdateNationLevel',
             'ProcessSemiAnnual',
             'ProcessWarIncome',
+            'CreateAdminNPC',
         ];
         if (!in_array($actionName, $supportedActions, true)) {
             throw new \InvalidArgumentException('unsupported monthly action');