[FIX] web_editor: copy paste link keeps the old url

Before this commit:

When we try to copy paste link into another link then url of the old link does
not change and only lable change.

After this commit:

Now when we try to copy paste link into another link then the url of the link
changes with the label.

Task-2768541

closes odoo/odoo#99569

Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>