website_mail: fix the save and continue issuse.

<b>Description:</b> in website_mail module fix the save and continue button issuse, using bind click event and call <code>editor_bar.save()</code> .

<b>Task:</b> https://www.odoo.com/web#id=9308&view_type=form&model=project.task&menu_id=3942&action=327
<b>Pad:</b> https://pad.odoo.com/p/r.n7EwGGKuLCsFZqUJ
Why do you attach your code to the EditorBar while it is actually used by a button outside the editor bar?