fix: refine placeholder rendering logic in MultipleContent component

bg: https://github.com/react-component/select/pull/1166/changes#r2707079879
fix: ant-design/ant-design#56587

Author: Wxh16144

src/SelectInput/Content/MultipleContent.tsx

@@ -200,7 +200,7 @@ export default React.forwardRef<HTMLInputElement, SharedContentProps>(function M
       prefixCls={`${prefixCls}-content`}
       className={classNames?.content}
       style={styles?.content}
-      prefix={!displayValues.length && (!searchValue || !triggerOpen) ? <Placeholder /> : null}
+      prefix={!displayValues.length && !searchValue && <Placeholder />}
       data={displayValues}
       renderItem={renderItem}
       renderRest={renderRest}