Description of the issue/feature this PR addresses:
Task : https://www.odoo.com/web#id=30428&view_type=form&model=project.task&action=333&active_id=131&menu_id=4720
Pad : https://pad.odoo.com/p/r.049d4059ff5ef3363ca2b82905299864
Current behavior before PR:
Desired behavior after PR is merged:
I confirm I have signed the CLA and read the PR guidelines at www.odoo.com/submit-pr
[IMP]mass_mailling:Disabaling the creation of mail if no email found.