### 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)
filter->clear();
	if (filters.size() > 1) {
		String all_filters;
		const int max_filters = 5;
		for (int i = 0; i < MIN(max_filters, filters.size()); i++) {
			String flt = filters[i].get_slice(";", 0).strip_edges();
			if (i > 0) {
				all_filters += ", ";
			}
			all_filters += flt;
		}
		if (max_filters < filters.size()) {
			all_filters += ", ...";
		}
		filter->add_item(TTR("All Recognized") + " (" + all_filters + ")");
	}
	for (int i = 0; i < filters.size(); i++) {
		String flt = filters[i].get_slice(";", 0).strip_edges();
		String desc = filters[i].get_slice(";", 1).strip_edges();
		if (desc.length()) {
			filter->add_item(desc + " (" + flt + ")");
		} else {
			filter->add_item("(" + flt + ")");
		}
	}
	filter->add_item(TTR("All Files (*)"));
}
void EditorFileDialog::clear_filters() {