Contact-editor now immediately shows proper editor for new fields.

Previously, when adding a new field via "Add new" or "Add another
field", an empty field appeared, but the user couldn't edit its
contents without first tapping on it.  Now the approperiate editor
UI pops up immediately (eg: when you add a new "event", a date-picker
pops up).

Bug: 5070818
Change-Id: I882a8202a6a76f73f3efd24734b0e0acdbcecac0