Feat: The bottom anchor of the agent node is only displayed when there is a downstream node #9869 (#10611)

### What problem does this PR solve?

Feat: The bottom anchor of the agent node is only displayed when there
is a downstream node #9869

### Type of change


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

web/src/components/ui/select.tsx

@@ -291,7 +291,7 @@ export const RAGFlowSelect = forwardRef<
           onReset={handleReset}
           allowClear={allowClear}
           ref={ref}
-          className={cn(triggerClassName, 'bg-bg-base')}
+          className={cn('bg-bg-base', triggerClassName)}
         >
           <SelectValue placeholder={placeholder}>{label}</SelectValue>
         </SelectTrigger>