docs: remove example external link referring use of archived repo (#1457)

Author: nchen000

docs/example-external.mdx

@@ -4,11 +4,6 @@ title: External Examples
 sidebar_label: External Examples
 ---
 
-## Code Samples
-
-- You can find more React Testing Library examples at
-  [https://react-testing-examples.netlify.app/](https://react-testing-examples.netlify.app/).
-
 ## Playground
 
 - An interactive sandbox with visual feedback on different queries