Be a little more lenient with panel-open gestures.

The code would not consider any drag that did not complete
the "peek" distance (the distance the panel opens when you
press and hold on the status bar; on tablets this is
statusbarheight + closehandleheight, and on phones it's
headerheight + closehandleheight) as a candidate for a
fling, and set that drag's effective velocity to 0.

This CL just removes that check. Now a fling must meet the
minimum linear velocity and minimum Y distance thresholds
(100dp/sec and 20dp, respectively) to change the position of
the panel (closed->open or open->closed).

Bug: 7390976
Change-Id: Ia0c2450f9fdf3f27b890aab240a155dad1ab052f