template:run fails without the --mail-to option

[staubichsauger]

After creating a template, the execution of it fails with the error 'The "--mail-to" option requires a value.'. Steps to reproduce (login to ChurchTools was successful, no mail server is set up):
ctcli migrate:group-member-hierarchy X Y,Z --no-testmode --remove-redundant-parent-members --add-template=LightTeams && ctcli template:run LightTeams

[staubichsauger]

If I remove the "mail-to":null option from the template's json file, it works as desired.