The comment dialog now supports light and dark modes, covering both the

standard comment editing UI and the Other Comments sidebar. A couple of

improvements to the UI have been made in the process, namely proper

centering of the issue/Markdown-related checkboxes and work on the issue

bar to ensure a more compact, vertical view.
A fix was also made to help avoid losing the comment dialog. It used to

be that using the scroll wheel on the text area or another part of the

comment dialog could result in scrolling the page far away from the

comment dialog. Now these events are caught, preventing that from

happening.
There's also one small color tweak. The dark mode variant of

-rb-p-draft-bg is now just a bit lighter, helping the dialog stand

out from the rest of the UI. This also brightens the Unified Draft

Banner, which also helps that stand out as well. This helps elevate

these interactive elements above the content.

Tested on light and dark modes.