Feat: Modify the style of the canvas operator node #3221 (#8261)

### What problem does this PR solve?

Feat: Modify the style of the canvas operator node #3221

### Type of change


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

web/src/pages/agent/canvas/node/handle.tsx

@@ -0,0 +1,17 @@
+import { cn } from '@/lib/utils';
+import { Handle, HandleProps } from '@xyflow/react';
+import { Plus } from 'lucide-react';
+
+export function CommonHandle({ className, ...props }: HandleProps) {
+  return (
+    <Handle
+      {...props}
+      className={cn(
+        'inline-flex justify-center items-center !bg-background-checked !size-4 !rounded-sm !border-none ',
+        className,
+      )}
+    >
+      <Plus className="size-3 pointer-events-none" />
+    </Handle>
+  );
+}