fix: badge when undefined (#501)

apps/web/src/app/app/(dashboard)/[workspaceSlug]/monitors/page.tsx

···
       monitorId,
       limit: 1,
     });
-    const lastStatusCode = ping && ping.length > 0 ? ping[0].statusCode : 0;
+    const lastStatusCode =
+      ping && ping.length > 0 ? ping[0].statusCode : undefined;
     return lastStatusCode;
   }
 
···
         getMonitorLastStatusCode(String(monitor.id)),
       ) || [],
     )
-  ).map((code) => (code.status === "fulfilled" && code.value) || 0);
+  ).map((code) => (code.status === "fulfilled" ? code.value : undefined));
 
   return (
     <div className="grid min-h-full grid-cols-1 grid-rows-[auto,1fr,auto] gap-6 md:grid-cols-2 md:gap-8">

apps/web/src/components/data-table/monitor/columns.tsx

···
 import { DataTableStatusBadge } from "../data-table-status-badge";
 import { DataTableRowActions } from "./data-table-row-actions";
 
-export const columns: ColumnDef<Monitor & { lastStatusCode?: number }>[] = [
+export const columns: ColumnDef<
+  Monitor & { lastStatusCode?: number | null }
+>[] = [
   {
     accessorKey: "name",
     header: "Name",