You should never do those things together, it's best practice to separate them - and I'll give you a good user story example why (this has happened to me).
Let's say there's a validation error on your form,
then the email will send when you click submit, with invalid values,
but the form will not submit,
then you will edit the form and correct the issue,
click submit, but another validation issue,
the email will send again, with invalid values,
but the form will not submit,
then you fix all the errors, click submit,
the third copy of the email will then send, a correct version
and your form will submit
by this time the recipient has three emails all with differing data, which one do they use?