missing $unset for cleared pickadate fields

[boustanihani]

When using pickadate and after clearing a date field, calling AutoForm.getFormValues('FormId').updateDoc will not contain $unset for the field cleared:

{
    type: Date,
    autoform: {
        type: "pickadate",
        pickadateOptions: {
            //...
        }
    },
}

I could also do a reproduction example if needed...

[Chun-Yang]

Please reproduce the bug. Can you consider using http://meteorpad.com/?
Thank you!