### 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
p_list->push_back(PropertyInfo(Variant::INT, "_spawnable_scene_count", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_EDITOR | PROPERTY_USAGE_ARRAY, "Auto Spawn List,scenes/"));
	List<String> exts;
	ResourceLoader::get_recognized_extensions_for_type("PackedScene", &exts);
	String ext_hint;
	for (const String &E : exts) {
		if (!ext_hint.is_empty()) {
			ext_hint += ",";
		}
		ext_hint += "*." + E;
	}
	for (uint32_t i = 0; i < spawnable_scenes.size(); i++) {
		p_list->push_back(PropertyInfo(Variant::STRING, "scenes/" + itos(i), PROPERTY_HINT_FILE, ext_hint, PROPERTY_USAGE_EDITOR));
	}
}
#endif
PackedStringArray MultiplayerSpawner::get_configuration_warnings() const {