fix(web): keep external link labels breakable under PR autolinks

#8812 routes link content through a linkChildren element that already wraps
children in MarkdownLinkContext. Passing that inside MarkdownExternalLinkContent
puts an element where it looks for the leading text it splits with <wbr/>, so a
long label became one unbreakable run and overflowed the chat column.

Pylon wraps the result instead of the children for exactly this reason. Caught by
ChatMarkdown.test.tsx.

Author: rynfar

apps/web/src/components/ChatMarkdown.tsx

@@ -2338,7 +2338,7 @@ function ChatMarkdown({
                 // makes the whole label one unbreakable run.
                 <MarkdownLinkContext value>
                   <MarkdownExternalLinkContent host={faviconHost} plainText={plainHastText(node)}>
-                    {linkChildren}
+                    {children}
                   </MarkdownExternalLinkContent>
                 </MarkdownLinkContext>
               ) : (