use native dialogs

scripts/config_manager.gd

@@ -63,6 +63,8 @@ var current_timesheet_file_path: String = "" setget set_current_timesheet_file_p
 
 
 func set_current_timesheet_file_path(value: String) -> void:
+	if current_timesheet_file_path == value:
+		return
 	timesheet = _load_timesheet(value)
 	if timesheet == null:
 		return