[FIX] web_editor: persist URL-like text transformation to link

Commit [1] separated the two responsabilites of _onURLInput: making
changes to the DOM and updating the UI, taking care that only the second
one is done at start.

But this broke the following functionality:

- Have a URL-like text (ex: odoo.com), select it and click the link icon
on the sidebar.
- The URL is deduced from the link's label.
- Click anywhere to close the sidebar.

Before [1], the link transformation would be kept. After it, it is not.
This happens because this is a particular case in which we want to apply
changes to the DOM at start time, as if a URL input event had happened.

This commit fixes it.

task-3284649

[1]: 54746012

Part-of: odoo/odoo#118676