Remove outdated comment about string children being deprecated in `ne…

…xt/link` (#30606)

* Bring back accidentally lost deprecation warning for using string as a children for `next/link`

* Wrap warning with the env check

* Remove warning, just go with removed comment about deprecation

packages/next/client/link.tsx

@@ -223,7 +223,6 @@ function Link(props: React.PropsWithChildren<LinkProps>) {
 
   let { children, replace, shallow, scroll, locale } = props
 
-  // Deprecated. Warning shown by propType check. If the children provided is a string (<Link>example</Link>) we wrap it in an <a> tag
   if (typeof children === 'string') {
     children = <a>{children}</a>
   }