fix(desktop): constrain timeline content width

Keep the timeline content wrapper from expanding to group-DM intro min-content width so message rows and their hover action bars stay inside the viewport.

Co-authored-by: Pinky <44b8e82baa6e0e254e0208d68f335c283c94e7b78dd1fa10d5a49d3f13dd0435@sprout-oss.stage.blox.sqprod.co>
Signed-off-by: Wes <wesbillman@users.noreply.github.com>

desktop/src/features/messages/ui/MessageTimeline.tsx

@@ -324,7 +324,7 @@ export const MessageTimeline = React.memo(function MessageTimeline({
                 showMessageList && !showIntro && "mt-auto",
               )}
               contentClassName={cn(
-                "flex flex-col gap-2",
+                "flex min-w-0 flex-col gap-2",
                 (showIntro || showGenericEmpty) && "min-h-full",
               )}
               loading={isLoading}