[FIX] web_editor: auto transforming email URL

Typing a URL + SPACE transforms the URL into a link.

Before this commit, email URLs were incorrectly prepended with
'https://'.

Because it is not desirable to automatically transform email URLs, this
commit disables link transformation for email URLs, leaving it only
active for http URLs.

task-3284649

Part-of: odoo/odoo#118676