Describe the bug

When adding a relative link in WYSIWYG (QuillJS), it's handled as an external link: it has the external link icon and also it opens in a new tab.

To Reproduce
Steps to reproduce the behavior:

1. Sign in as admin
2. Edit a participatory process
3. Add a relative link in the short description. Save
4. Go to the process public page. See error

Expected behavior
To be a relative link, without external link icon and opening in the same tab.

Screenshots

Extra data (please complete the following information):

• Decidim Version: v0.27.0.dev

Additional context
Detected originally by @sdelcroix in Matrix.