Refine toggleDatePickerDrawerAppearance to take custom animation params.
Mitigate AutoLayout warning from conflicting constraints.

This time from not collapsing the drawer in time
for the keyboard.
Mitigate AutoLayout warning from conflicting constraints.

This time from not expanding the drawer too early.

This all feels super dirty, btw.
Minor renaming.
Refactor dispatch_after using new overloaded sugar.