src/view.c: Prevent crash by killing a moving application

src/view.c: Prevent crash by killing a moving application

When a view is destroyed labwc calls interactive_end(view) which
may reposition the view which is partly destroyed and doesn't own
any surface anymore. To prevent this scenario from happening don't
call interactive_end() at all and just reset server->grabbed_view
and server->input_mode directly.

Before this patch, the bug could be reproduced by:
- xcalc &
- sleep 5; killall xcalc
- move the xcalc window completely to one of the edges

The change in src/xwayland.c is not required for this bug
to be fixed but may prevent something similar in the future.