Describe the bug

When I open an external link that contains non-ASCII characters, it returns the "Invalid URL" error.

To Reproduce

1. Call the link controller with an external_url with non-ASCII characters. For example: http://localhost:3000/link?external_url=https://twitter.com/hashtag/ConsellGrassotGràciaNova

Expected behavior

It should encode the URL and give us the chance to redirect the user to it.

Screenshots

Stacktrace

0> URI.parse(params[:external_url])
=> URI must be ascii only "https://twitter.com/hashtag/ConsellGrassotGr\u00E0ciaNova"

Extra data

• Device: Desktop
• Device OS: MacOS 13.4.1
• Browser: Firefox
• Decidim Version: Reproduced on 0.26, 0.27 and 0.28
• Decidim installation: Detected on Decidim Barcelona, tested locally on the development app

Additional context

No response