### 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
make_dir_dialog = memnew(DirectoryCreateDialog);
	add_child(make_dir_dialog);
	make_dir_dialog->connect("dir_created", callable_mp(this, &FileSystemDock::_rescan));
	make_scene_dialog = memnew(SceneCreateDialog);
	add_child(make_scene_dialog);
	make_scene_dialog->connect("confirmed", callable_mp(this, &FileSystemDock::_make_scene_confirm));
	make_script_dialog = memnew(ScriptCreateDialog);
	make_script_dialog->set_title(TTR("Create Script"));
	add_child(make_script_dialog);
	make_shader_dialog = memnew(ShaderCreateDialog);
	add_child(make_shader_dialog);
	new_resource_dialog = memnew(CreateDialog);
	add_child(new_resource_dialog);
	new_resource_dialog->set_base_type("Resource");
	new_resource_dialog->connect("create", callable_mp(this, &FileSystemDock::_resource_created));
	searched_string = String();
	uncollapsed_paths_before_search = Vector<String>();
	tree_update_id = 0;
	history_pos = 0;
	history_max_size = 20;
	history.push_back("res://");
	display_mode = DISPLAY_MODE_TREE_ONLY;
	old_display_mode = DISPLAY_MODE_TREE_ONLY;
	file_list_display_mode = FILE_LIST_DISPLAY_THUMBNAILS;
	add_resource_tooltip_plugin(memnew(EditorTextureTooltipPlugin));
}
FileSystemDock::~FileSystemDock() {
	singleton = nullptr;
}