Show either a next or okay button in gettingstartedtasktoolbar edit step.

Also applies to gettingstartedtasktoolbarve tour.
For optional next buttons, one must set allowAutomaticNext to false.
Next button shown if there is an edit section, okay otherwise.
Bug: 67907

Change-Id: I1c511358837ad9fcdc886030a91386999228635a
Merge "Show either a next or okay button in gettingstartedtasktoolbar edit step."