### 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
if ((file_list_vb->is_visible_in_tree() || current_path == p_path.get_base_dir()) && p_preview.is_valid()) {
		Array uarr = p_udata;
		int idx = uarr[0];
		String file = uarr[1];
		if (idx < files->get_item_count() && files->get_item_text(idx) == file && files->get_item_metadata(idx) == p_path) {
			if (file_list_display_mode == FILE_LIST_DISPLAY_LIST) {
				if (p_small_preview.is_valid()) {
					files->set_item_icon(idx, p_small_preview);
				}
			} else {
				files->set_item_icon(idx, p_preview);
			}
		}
	}
}
void FileSystemDock::_tree_thumbnail_done(const String &p_path, const Ref<Texture2D> &p_preview, const Ref<Texture2D> &p_small_preview, const Variant &p_udata) {
	if (p_small_preview.is_valid()) {
		Array uarr = p_udata;
		if (tree_update_id == (int)uarr[0]) {
			TreeItem *file_item = Object::cast_to<TreeItem>(uarr[1]);
			if (file_item) {
				file_item->set_icon(0, p_small_preview);
			}
		}
	}
}
void FileSystemDock::_toggle_file_display() {