[BUG] Using a 0 (zero) value in a choice field prevents correct display in mails

[alexej-d]

I have observed a curious case:

• Create a form with a choice type field.
• Create a value 0 with a random option name and create another option.
• Setup the submission of the form data via mail.
• When a form is submitted and the value of the choice field is "0", the field value is incorrectly displayed in the mail, otherwise the option name is used.