fix [#22007] Saving a read-only file on windows : no warning and temporary files left there

* return OPERATOR_FINISHED from file save, so reports are not suppressed - this results in popup with the expected error in this case.

source/blender/windowmanager/intern/wm_operators.c

@@ -1796,7 +1796,7 @@ static int wm_save_as_mainfile_exec(bContext *C, wmOperator *op)
 	
 	WM_event_add_notifier(C, NC_WM|ND_FILESAVE, NULL);
 
-	return 0;
+	return OPERATOR_FINISHED;
 }
 
 static void WM_OT_save_as_mainfile(wmOperatorType *ot)