### 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
add_child(split_box);
	tree = memnew(FileSystemTree);
	tree->set_hide_root(true);
	SET_DRAG_FORWARDING_GCD(tree, FileSystemDock);
	tree->set_allow_rmb_select(true);
	tree->set_select_mode(Tree::SELECT_MULTI);
	tree->set_custom_minimum_size(Size2(0, 15 * EDSCALE));
	tree->set_column_clip_content(0, true);
	split_box->add_child(tree);
	tree->connect("item_activated", callable_mp(this, &FileSystemDock::_tree_activate_file));
	tree->connect("multi_selected", callable_mp(this, &FileSystemDock::_tree_multi_selected));
	tree->connect("item_mouse_selected", callable_mp(this, &FileSystemDock::_tree_rmb_select));
	tree->connect("empty_clicked", callable_mp(this, &FileSystemDock::_tree_empty_click));
	tree->connect("nothing_selected", callable_mp(this, &FileSystemDock::_tree_empty_selected));
	tree->connect("gui_input", callable_mp(this, &FileSystemDock::_tree_gui_input));
	tree->connect("mouse_exited", callable_mp(this, &FileSystemDock::_tree_mouse_exited));
	tree->connect("item_edited", callable_mp(this, &FileSystemDock::_rename_operation_confirm));
	file_list_vb = memnew(VBoxContainer);
	file_list_vb->set_v_size_flags(SIZE_EXPAND_FILL);
	split_box->add_child(file_list_vb);
	path_hb = memnew(HBoxContainer);
	file_list_vb->add_child(path_hb);
	file_list_search_box = memnew(LineEdit);
	file_list_search_box->set_h_size_flags(SIZE_EXPAND_FILL);
	file_list_search_box->set_placeholder(TTR("Filter Files"));
	file_list_search_box->connect("text_changed", callable_mp(this, &FileSystemDock::_search_changed).bind(file_list_search_box));
	path_hb->add_child(file_list_search_box);
	file_list_button_sort = _create_file_menu_button();
	path_hb->add_child(file_list_button_sort);
	button_file_list_display_mode = memnew(Button);