Replace alert() with console.log() (#3656)

[denizbinay]

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The following Chromium feature is currently being tested. "Feature: Remove alert(), confirm(), and prompt for cross origin iframes§ https://www.chromestatus.com/feature/5148698084376576

Therefore, alert() will no longer work on Codepen. console.log() still works. The feature is not yet in the stable version of Chromium, but in the current beta (tested with Chrome beta version 91.0.4472.27).

[reactjs-bot]

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[BartoszKlonowski]

Hello @denizbinay, thank you for contributing! Can you check whether now, (after those years 🙃 ) this is really the case and alert does cause issues on the react.dev? If yes, then please rebase so I would look into this PR. 👍 Thank you!