Remove trailing whitespaces
Unit create/kill menu actions (debug mode): temporarily disable animations

This is a workaround for bug #18921 for Wesnoth 1.12 to avoid segfaults
(or asserts) caused by a debug action being triggered while another
animation is playing. It only affects creating or killing units in
debug mode from the right-click content menu, all other animations
remain unchanged. The full fix will require refactoring of the
animation code. This will happen in 1.13/1.14, after which these
animations will be enabled again.