Reduce pum redraws from edit.c by delaying undisplay of pum

This makes it possible for the compositor to compare the old pum with
the new position, and only clear what is necessary.

src/nvim/screen.c

@@ -7203,7 +7203,6 @@ void screen_resize(int width, int height)
       } else {
         update_topline();
         if (pum_drawn()) {
-          redraw_later(NOT_VALID);
           ins_compl_show_pum();
         }
         update_screen(NOT_VALID);