misc(FR-1940): Modify the upload dropdown button to open only when clicked (#5104)

Author: nowgnuesLee

packages/backend.ai-ui/src/components/baiClient/FileExplorer/ExplorerActionControls.tsx

@@ -95,6 +95,7 @@ const ExplorerActionControls: React.FC<ExplorerActionControlsProps> = ({
         </Tooltip>
         <Dropdown
           disabled={!enableWrite}
+          trigger={['click']}
           popupRender={() => {
             return (
               <BAIFlex