fix(linq): mark list_phone_numbers healthStatus output nullable

healthStatus returns null when Linq omits reputation/health_status; declare
nullable: true to match the runtime value (same as forwardingNumber).

Author: waleedlatif1

apps/sim/tools/linq/list_phone_numbers.ts

@@ -72,6 +72,7 @@ export const linqListPhoneNumbersTool: ToolConfig<
           healthStatus: {
             type: 'json',
             description: 'Line reputation/health status (status, doc_url)',
+            nullable: true,
           },
         },
       },