`win->ime_data` could be non-null when it's read from a file, and
subsequent dependence of this value would crash on interface handlers.
Now always clear it when ghost window is ensured after reading the file.
The actual reset is put in `wm_window_ensure_eventstate`, since it's
also conceptually a part of "event state".
Pull Request: https://projects.blender.org/blender/blender/pulls/136833
78c0ca1efb