Feat: The keys for data manipulation operators can only be numbers, letters, and underscores. #10427 (#11130)

### What problem does this PR solve?

Feat: The keys for data manipulation operators can only be numbers,
letters, and underscores. #10427

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/agent/canvas/node/variable-aggregator-node.tsx

@@ -22,7 +22,7 @@ export function VariableAggregatorNode({
               <span className="text-text-secondary">{x.type}</span>
             </div>
             <div className="space-y-1">
-              {x.variables.map((y, index) => (
+              {x.variables?.map((y, index) => (
                 <LabelCard key={index} className="truncate">
                   {getLabel(y.value)}
                 </LabelCard>