don't set due date immediately when clicking on set due date

[mokkin]

When you set the first time a due date of a card, a value like 7 a.m. of the next day is choosen. After this is set, the user can use the date picker and edit the due date.
This first "fake" setting of 7 a.m. in the morning should be avoided, because it also creates useless events in the activitiy app and notifications of a false due day set.

Deck v1.12.2

In the example the correct first set date would be March, 29th instead of 21st.