When cloning a growth session the date should not use the previous date as a default.

[nickdown]

Currently when cloning a growth session the date in the form defaults to the day of the growth session that is being cloned.

Often times that will be the previous session, which will be in the past and is not valid to create.
This causes an error upon submission if the date is not changed.

Either the date field could be empty and force the user to pick a date, or it should default to the current date.