Fix T100887: Some C++ importers/exporters (e.g. OBJ) reset file dialog Sort By mode

A couple years ago D8598 made it so that C++ operators generally
should use "default" sort mode, which remembers previously used sort
setting. Back then all the places that needed it got changed to use
this "default" one, but since then some more IO code landed, where
seemingly by accident it used "sort by file name":

- USD importer,
- Grease Pencil exporter,
- OBJ importer & exporter,
- STL importer.

Reviewed By: Julian Eisel
Differential Revision: https://developer.blender.org/D15906

source/blender/editors/io/io_gpencil_export.c

@@ -217,7 +217,7 @@ void WM_OT_gpencil_export_svg(wmOperatorType *ot)
                                  FILE_SAVE,
                                  WM_FILESEL_FILEPATH | WM_FILESEL_SHOW_PROPS,
                                  FILE_DEFAULTDISPLAY,
-                                 FILE_SORT_ALPHA);
+                                 FILE_SORT_DEFAULT);
 
   gpencil_export_common_props_definition(ot);
 
@@ -375,7 +375,7 @@ void WM_OT_gpencil_export_pdf(wmOperatorType *ot)
                                  FILE_SAVE,
                                  WM_FILESEL_FILEPATH | WM_FILESEL_SHOW_PROPS,
                                  FILE_DEFAULTDISPLAY,
-                                 FILE_SORT_ALPHA);
+                                 FILE_SORT_DEFAULT);
 
   static const EnumPropertyItem gpencil_export_frame_items[] = {
       {GP_EXPORT_FRAME_ACTIVE, "ACTIVE", 0, "Active", "Include only active frame"},

source/blender/editors/io/io_obj.c

@@ -266,7 +266,7 @@ void WM_OT_obj_export(struct wmOperatorType *ot)
                                  FILE_SAVE,
                                  WM_FILESEL_FILEPATH | WM_FILESEL_SHOW_PROPS,
                                  FILE_DEFAULTDISPLAY,
-                                 FILE_SORT_ALPHA);
+                                 FILE_SORT_DEFAULT);
 
   /* Animation options. */
   RNA_def_boolean(ot->srna,
@@ -494,7 +494,7 @@ void WM_OT_obj_import(struct wmOperatorType *ot)
                                  WM_FILESEL_FILEPATH | WM_FILESEL_SHOW_PROPS |
                                      WM_FILESEL_DIRECTORY | WM_FILESEL_FILES,
                                  FILE_DEFAULTDISPLAY,
-                                 FILE_SORT_ALPHA);
+                                 FILE_SORT_DEFAULT);
   RNA_def_float(
       ot->srna,
       "clamp_size",

source/blender/editors/io/io_stl_ops.c

@@ -104,7 +104,7 @@ void WM_OT_stl_import(struct wmOperatorType *ot)
                                  WM_FILESEL_FILEPATH | WM_FILESEL_FILES | WM_FILESEL_DIRECTORY |
                                      WM_FILESEL_SHOW_PROPS,
                                  FILE_DEFAULTDISPLAY,
-                                 FILE_SORT_ALPHA);
+                                 FILE_SORT_DEFAULT);
 
   RNA_def_float(ot->srna, "global_scale", 1.0f, 1e-6f, 1e6f, "Scale", "", 0.001f, 1000.0f);
   RNA_def_boolean(ot->srna,

source/blender/editors/io/io_usd.c

@@ -487,7 +487,7 @@ void WM_OT_usd_import(struct wmOperatorType *ot)
                                  FILE_OPENFILE,
                                  WM_FILESEL_FILEPATH | WM_FILESEL_RELPATH | WM_FILESEL_SHOW_PROPS,
                                  FILE_DEFAULTDISPLAY,
-                                 FILE_SORT_ALPHA);
+                                 FILE_SORT_DEFAULT);
 
   RNA_def_float(
       ot->srna,