Konsole sends up/down key press events for mouse scrolls apps that aren't
interested in mouse events, such as less. Only do this when the terminal
is using the alternate screen.
Sending up/down key press events when the terminal is using the primary
screen has side effect of scrolling through the shell history which is
inconsistent with other terminal emulators.
BUG: 355106
FIXED-IN: 18.04