### Godot version

v4.1.rc2.official [46424488e]

### System information

Godot v4.1.rc2 - Linux Mint 20 (Ulyana) - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2060 SUPER (nvidia; 515.105.01) - Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz (8 Threads)

### Issue description

Dragging and dropping a file to a new position inside its current folder, or onto the icon for its current folder - when that folder is the project root folder :res// - will be treated as though you were dropping a different file with the same name.

Expectation: for nothing to happen.

Also tried it in 4.0.3 and 4.1-dev3, where it behaves as expected.

https://github.com/godotengine/godot/assets/64640811/90de1120-dd92-41b8-b202-db77c343103a

### Steps to reproduce

1. New or existing project.
2. Click and drag a file in :res// in FileSystem dock.
3. Drop the file back into :res//.
4. Be prompted to overwrite or rename.

### Minimal reproduction project

N/A
HashSet<String> cselection;
	if (p_keep_selection) {
		for (int i = 0; i < files->get_item_count(); i++) {
			if (files->is_selected(i)) {
				cselection.insert(files->get_item_text(i));
			}
		}
	}
	files->clear();
	_set_current_path_line_edit_text(current_path);
	String directory = current_path;
	String file = "";
	int thumbnail_size = EDITOR_GET("docks/filesystem/thumbnail_size");
	thumbnail_size *= EDSCALE;
	Ref<Texture2D> folder_thumbnail;
	Ref<Texture2D> file_thumbnail;
	Ref<Texture2D> file_thumbnail_broken;
	bool use_thumbnails = (file_list_display_mode == FILE_LIST_DISPLAY_THUMBNAILS);
	if (use_thumbnails) {
		
		files->set_max_columns(0);
		files->set_icon_mode(ItemList::ICON_MODE_TOP);
		files->set_fixed_column_width(thumbnail_size * 3 / 2);
		files->set_max_text_lines(2);