touchpad: Only break out of tap FSM for clickpad button presses

touchpad: Only break out of tap FSM for clickpad button presses

It should be possible to initiate a drag by tapping-drag, but continue
it by pressing a physical button continuing to drag by subsequent finger
motions.

As the generic evdev layer helps us ignore multiple button presses we
can have the tap machine run completely separate from and uneffected by
regular physical button presses, making the tap FSM much simpler than
adding new states for handling button presse life times from outside
of the tap state machine.

A touchpad test is updated to test click while tapping instead of tap
FSM break out. The updated test is re-added but only for clickpads only.

The tap FSM svg is updated to say "clickpad button press" instead of
"phys button press".

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>