fix: Fixed the issue of error reporting when uploading files in the chat box #2897 (#2898)

### What problem does this PR solve?

fix: Fixed the issue of error reporting when uploading files in the chat
box #2897

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

web/src/pages/chat/markdown-content/index.tsx

@@ -118,7 +118,11 @@ const MarkdownContent = ({
             {documentId && (
               <Flex gap={'small'}>
                 {fileThumbnail ? (
-                  <img src={fileThumbnail} alt="" />
+                  <img
+                    src={fileThumbnail}
+                    alt=""
+                    className={styles.fileThumbnail}
+                  />
                 ) : (
                   <SvgIcon
                     name={`file-icon/${fileExtension}`}