Revert "workspaceAnimation: Allow long swipes in session"

Revert "workspaceAnimation: Allow long swipes in session"

The behavior when switching workspaces now with the touchpad gesture is
very very weird, it almost always swipes to the last workspace instead
of the next one.

So revert this change again and only swipe a single page per gesture. We
can enable long swipes again when we've figured out a proper way to
detect what the user wants (which is going to be quite challenging), see
https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4355.

This reverts commit dfae3281b9a7fe6f5ccb6e9c175591a5ce31fd73.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1933>