improvment: email test

[matdemb]

Hi
when we enter an email adress in "add recipient" the interface doesn't test if the mail is correct (for syntax).
example:

We obtain an error only when we validate the sharing, but the sender receive a confirmation mail for the share.
It would be great to have a test to check if the email address looks like an email address.

Kind regards,

[wboudiche]

Thank you for the proposal, we will consider it in our backlog