MDL-76010 behat: Move feature to use attempts generator
This moves away from manual attempts and uses the activity
attempts generator instead. Quicker and not exposed to the
problems with clicks, refreshes and missing attempts.
Note that there is a small change in the attempt generator
so, now, when a new attempt is created, if the activity has
tracking enabled, the final result / grades are recalculated.
That's the real behaviour when the activity settings are
changes in the edition form and it's natural to get them
recalculated without having to visit the form. Specifically,
this allows the 1st scenario to pass, because in that scenario
no changes to the form are being performed.
Also, little detail, amend a dupe scenario name.