UI: Fix help widget sidebar colours in dark mode

[kartikktripathi]

Summary

When PR #5165 was merged, it unintentionally affected the help widget sidebars in dark mode, causing them to render with an inconsistent colour compared to the rest of the UI. This PR fixes that issue by restoring the correct sidebar styling in dark mode, ensuring visual consistency across the help widget.

Before:

After:

Note

1. No functional changes
2. Styling fix only

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[kartikktripathi]

Hey @walterbender, pinging for the review, no rush. I believe the change can provide users with a better help widget UI. Thanks!

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[walterbender]

I see lots of formatting changes but where is the actual change you made that impacts the side colors? Also, please resolve the conflicts.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[walterbender]

I am still seeing this:

[kartikktripathi]

It seems like a change was made by another PR that affected the colour of the main body of the widget in dark mode. I will check the changes responsible for the same, make the changes that are required and get back to you.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[kartikktripathi]

I found the PR that caused a conflict. When #5303 was merged, it focused on the main body of the widget and not the sidebars, causing you to see a difference in the colours, which looks odd, I agree. When I raised this PR, I had the idea of keeping the body colour constant, totally, for the help widget, which is why I commented the correct line, but if #5303 keeps #505050 as the primary background colour of the help widget for visibility (which is important too, I agree), the sidebars should be of the same color as the background colour of the main body.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[kartikktripathi]

I have tested the finalised changes by me; it looks good to me, visibility is fine, and there is a constant colour across the widget too. Thanks!