fix(files): make the rich-markdown-field container a positioning context (#6435)

rich-markdown-field also mounts EditorBubbleMenu with its own container ref, so
the same 'relative' the editor container needs applies here — otherwise the
absolutely-positioned toolbar resolves against the wrong offset parent and scroll
tracking breaks in the field. Safe in both modes: 'relative' adds no offset and no
clipping to the uncapped (page-scrolls) box.

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/rich-markdown-field.tsx

@@ -182,7 +182,9 @@ function LoadedRichMarkdownField({
     <div
       ref={containerRef}
       className={cn(
-        'flex flex-col px-3 py-2',
+        // `relative` makes this the positioning context for the bubble menu, which is
+        // appended here and absolutely positioned so it tracks the selection through scroll.
+        'relative flex flex-col px-3 py-2',
         // Only a capped box scrolls itself. Uncapped, the box grows and the page
         // scrolls — making it a scroll container anyway would clip the bubble
         // menu against an edge that never moves.