Removal of the WM_redraw_windows call in wm_file_write introduced
in rB7a9cfd08a8d7415ff004809cf62570be9152273e as that can cause
crashing while saving from a script.

Calling WM_redraw_windows in wm_file_write had been added in D12507 to ensure that there were no menus shown open during the process to ensure screenshot-type thumbnails did not capture them. However we don't currently have a reliable way to do this that does not cause crashing when saving from scripts, as illustrated in T92704 & T97627. This patch removes that call and adds a descriptive comment in its place.