### Godot version

4.1.1

### System information

linux

### Issue description

- When favoriting a path in a `FileDialog`, clicking on it travels to `path/to/dir/`.
- When going up a level from there, it doesn't go to `path/to` but to `path/to/dir` (without the `/`).

[simplescreenrecorder-2023-08-18_09.38.37.webm](https://github.com/godotengine/godot/assets/71937306/00c20ad3-292f-4961-84ed-dbc64906df52)

The problem is either (or both) that:
 - loaded path has a trailing `/`
 - parent dir of `stuff/` is considered to be `stuff`

### Steps to reproduce

favorite a directory and use the feature to navigate to it

### Minimal reproduction project

any (i.e. the project manager's "new project" dialog has one)
local_history.resize(local_history_pos + 1);
	String new_path = dir_access->get_current_dir();
	if (local_history.size() == 0 || new_path != local_history[local_history_pos]) {
		local_history.push_back(new_path);
		local_history_pos++;
		dir_prev->set_disabled(local_history_pos == 0);
		dir_next->set_disabled(true);
	}
}
void EditorFileDialog::_item_dc_selected(int p_item) {