Render MessageReasoning only if text is present (#1082)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

components/message.tsx

@@ -103,7 +103,7 @@ const PurePreviewMessage = ({
               const { type } = part;
               const key = `message-${message.id}-part-${index}`;
 
-              if (type === 'reasoning') {
+              if (type === 'reasoning' && part.text?.trim().length > 0) {
                 return (
                   <MessageReasoning
                     key={key}