Feat: Add child nodes and their connecting lines by clicking #3221 (#8314)

### What problem does this PR solve?
Feat: Add child nodes and their connecting lines by clicking #3221

### Type of change


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

web/src/pages/agent/canvas/node/dropdown/next-step-dropdown.tsx

@@ -30,8 +30,8 @@ function OperatorItemList({ operators }: OperatorItemProps) {
             key={x}
             className="hover:bg-background-card py-1 px-3 cursor-pointer rounded-sm flex gap-2 items-center justify-start"
             onClick={addCanvasNode(x, {
-              id: nodeId,
-              sourceHandle: id,
+              nodeId,
+              id,
               position,
             })}
           >