### 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
Vector<String> selected_strings = _tree_get_selected(false);
	
	switch (p_option) {
		case FOLDER_EXPAND_ALL:
		case FOLDER_COLLAPSE_ALL: {
			
			if (selected_strings.size() == 1) {
				tree->get_selected()->set_collapsed_recursive(p_option == FOLDER_COLLAPSE_ALL);
			}
		} break;
		default: {
			_file_option(p_option, selected_strings);
		} break;
	}
}
void FileSystemDock::_file_list_rmb_option(int p_option) {