### 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
TreeItem *selected = tree->get_selected();
	if (selected) {
		String file_path = selected->get_metadata(0);
		TreeItem *parent = selected->get_parent();
		bool is_favorite = parent != nullptr && parent->get_metadata(0) == "Favorites";
		if ((!is_favorite && file_path.ends_with("/")) || file_path == "Favorites") {
			bool collapsed = selected->is_collapsed();
			selected->set_collapsed(!collapsed);
		} else {
			_select_file(file_path, is_favorite && !file_path.ends_with("/"));
		}
	}
}
void FileSystemDock::_file_list_activate_file(int p_idx) {
	_select_file(files->get_item_metadata(p_idx));
}
void FileSystemDock::_preview_invalidated(const String &p_path) {