Follow up to D15904, a bunch of places had exact same logic for "is filepath set? if not, set some default one", so factor all that out into a separate ED_fileselect_ensure_default_filepath function.
Follow up to D15904, a bunch of places had exact same logic for "is filepath set? if not, set some default one", so factor all that out into a separate ED_fileselect_ensure_default_filepath function.