Fix mobile nav layering

https://twitter.com/hisafira/status/1636639994990452737

beta/src/components/Layout/TopNav/TopNav.tsx

@@ -290,7 +290,7 @@ export default function TopNav({
         {isOpen && (
           <div
             ref={scrollParentRef}
-            className="overflow-y-scroll no-bg-scrollbar lg:w-[342px] grow bg-wash dark:bg-wash-dark">
+            className="overflow-y-scroll isolate no-bg-scrollbar lg:w-[342px] grow bg-wash dark:bg-wash-dark">
             <aside
               className={cn(
                 `lg:grow lg:flex flex-col w-full pb-8 lg:pb-0 lg:max-w-xs z-50`,