Extension selector behind ALPHA flag (#5892)

Author: zanesq

ui/desktop/src/components/ChatInput.tsx

@@ -1493,7 +1493,7 @@ export default function ChatInput({
           </Tooltip>
           <div className="w-px h-4 bg-border-default mx-2" />
           <BottomMenuModeSelection />
-          {sessionId && (
+          {sessionId && process.env.ALPHA && (
             <>
               <div className="w-px h-4 bg-border-default mx-2" />
               <BottomMenuExtensionSelection sessionId={sessionId} />