### Godot version

4.1.beta.a83eb16fb

### System information

Arch Linux

### Issue description

When attempting to have a scene load a resource that uses a script that exports a var of Callable type, a parse error will occur due to Callable not being serializable.

### Steps to reproduce

Create new project.
create a resource script that exports a Callable type:

```
class_name BreakStuff
extends Resource
@export var something: Callable
```

create a .tres file that uses the script.

create a scene that uses that resource, such as with a script like

```
extends Node
@export var stuff: Resource
```

set that resource to that .tres file.

close project and reopen.

Be greeted with error message about a parse error and be unable to open that scene.

Within plain text of .tscn file you can see a line that reads
something =

which causes a parse error as something has nothing to be set to.



### Minimal reproduction project

N/A
clear_spawnable_scenes();
	for (int i = 0; i < p_scenes.size(); i++) {
		add_spawnable_scene(p_scenes[i]);
	}
}
void MultiplayerSpawner::_bind_methods() {
	ClassDB::bind_method(D_METHOD("add_spawnable_scene", "path"), &MultiplayerSpawner::add_spawnable_scene);
	ClassDB::bind_method(D_METHOD("get_spawnable_scene_count"), &MultiplayerSpawner::get_spawnable_scene_count);
	ClassDB::bind_method(D_METHOD("get_spawnable_scene", "index"), &MultiplayerSpawner::get_spawnable_scene);
	ClassDB::bind_method(D_METHOD("clear_spawnable_scenes"), &MultiplayerSpawner::clear_spawnable_scenes);
	ClassDB::bind_method(D_METHOD("_get_spawnable_scenes"), &MultiplayerSpawner::_get_spawnable_scenes);
	ClassDB::bind_method(D_METHOD("_set_spawnable_scenes", "scenes"), &MultiplayerSpawner::_set_spawnable_scenes);
	ADD_PROPERTY(PropertyInfo(Variant::PACKED_STRING_ARRAY, "_spawnable_scenes", PROPERTY_HINT_NONE, "", (PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_INTERNAL)), "_set_spawnable_scenes", "_get_spawnable_scenes");
	ClassDB::bind_method(D_METHOD("spawn", "data"), &MultiplayerSpawner::spawn, DEFVAL(Variant()));
	ClassDB::bind_method(D_METHOD("get_spawn_path"), &MultiplayerSpawner::get_spawn_path);
	ClassDB::bind_method(D_METHOD("set_spawn_path", "path"), &MultiplayerSpawner::set_spawn_path);
	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "spawn_path", PROPERTY_HINT_NONE, ""), "set_spawn_path", "get_spawn_path");
	ClassDB::bind_method(D_METHOD("get_spawn_limit"), &MultiplayerSpawner::get_spawn_limit);
	ClassDB::bind_method(D_METHOD("set_spawn_limit", "limit"), &MultiplayerSpawner::set_spawn_limit);
	ADD_PROPERTY(PropertyInfo(Variant::INT, "spawn_limit", PROPERTY_HINT_RANGE, "0,1024,1,or_greater"), "set_spawn_limit", "get_spawn_limit");
	ClassDB::bind_method(D_METHOD("get_spawn_function"), &MultiplayerSpawner::get_spawn_function);
	ClassDB::bind_method(D_METHOD("set_spawn_function", "spawn_function"), &MultiplayerSpawner::set_spawn_function);
	ADD_PROPERTY(PropertyInfo(Variant::CALLABLE, "spawn_function", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR), "set_spawn_function", "get_spawn_function");
	ADD_SIGNAL(MethodInfo("despawned", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Node")));
	ADD_SIGNAL(MethodInfo("spawned", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Node")));
}
void MultiplayerSpawner::_update_spawn_node() {