[Chats] No scrollbar in preview panel for .md files — content beyond viewport is inaccessible

[dariacherepanova]

DIAL chat version

0.0.1

How to reproduce

PRE-CONDITIONS:
A conversation contains a .md file whose content is longer than the visible area of the preview panel.

TEST STEPS:

1. Open a chat containing a .md file attachment.
2. Click the .md file to open its preview panel.
3. Attempt to scroll down within the preview panel to view content below the fold.

repro_markdown_preview_scroll_bug.md

Actual result

There is no scrollbar in the .md preview panel, and the user cannot scroll to see content beyond what is initially visible, making part of the file's content inaccessible in the preview.

Expected result

The preview panel should have a functional scrollbar (or support mouse-wheel/keyboard scrolling), allowing the user to view all content of the .md file, including content below the initially visible area.

Confidential information

• I confirm that do not share any confidential information

[dariacherepanova]

Reopen - Retested in dev, there's still no scrollbar