Drawer/chat accessibility fixes

[jonkafton]

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/7082

Description (What does it do?)

Addresses the competing close buttons on the syllabus drawer with a rotating chevron for slide down/up.

Upgrades Smoot Design for:

mitodl/smoot-design#92

• Chat prompt input should receive focus after submit from entry screen (text inut and starters buttons).
• High: Entry screen conversation starter buttons should have a natural tab order (tabindex: 0).
• High: Entry screen prompt submit needs a label for screen readers.
• Entry screen prompt input should have more prominent focus styles (match blue border on starts buttons).
• Add structure and mechanisms to navigate the messages thread for screen readers.

mitodl/smoot-design#93

• fix: Remove double indent for chat message ordered lists

Adds a requestAnimationFrame to wait for first render before scrolling to the top - fixes an issue where the drawer opened with content scrolled to bottom.

Screenshots (if appropriate):

Screen.Recording.2025-04-24.at.17.57.02.mov

How can this be tested?

You'll need to set chatEnabled to true in LearningResourceExpanded.tsx to bypass the Posthog setting. Open the drawer on a course and open/close the AskTIM slidedown.

Additional Context

We've pulled out the drawer limited content at zoom item as designs are in flight and it's covered by an earlier ticket (https://github.com/mitodl/hq/issues/6513). This branch captures the wip design.

• High: The syllabus drawer messages thread needs more space at page zoom magnification - the drawer header area limits space further). At 200% only a couple of lines are visible. At 300% it is obscured completely.

[github-actions]

OpenAPI Changes

Show/hide No detectable change.

[gumaerc]

Looks good!

[github-actions]

OpenAPI Changes

Show/hide No detectable change.