### Godot version

4.2 f7bc653

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

`get_method()`:
```
Returns the name of the method represented by this Callable. If the callable is a lambda function, returns the function's name
```
However calling it on a named lambda results in
```
Can't get method on CallableCustom "test(lambda)".
```
(ironically the error even contains the function's name...)

`get_method()` in GDScriptLambdaCallable is likely unimplemented or is wrong. It should work for named lambdas.

### Steps to reproduce

```GDScript
var fun = func test(): pass
print(fun.get_method())
```

### Minimal reproduction project

N/A
return compare_equal;
}
CallableCustom::CompareLessFunc GDScriptRPCCallable::get_compare_less_func() const {
	return compare_less;
}
ObjectID GDScriptRPCCallable::get_object() const {
	return object->get_instance_id();
}
void GDScriptRPCCallable::call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const {
	r_return_value = object->callp(method, p_arguments, p_argcount, r_call_error);
}
GDScriptRPCCallable::GDScriptRPCCallable(Object *p_object, const StringName &p_method) {
	object = p_object;
	method = p_method;
	h = method.hash();
	h = hash_murmur3_one_64(object->get_instance_id(), h);
	node = Object::cast_to<Node>(object);
	ERR_FAIL_COND_MSG(!node, "RPC can only be defined on class that extends Node.");
}
Error GDScriptRPCCallable::rpc(int p_peer_id, const Variant **p_arguments, int p_argcount, Callable::CallError &r_call_error) const {
	if (unlikely(!node)) {
		r_call_error.error = Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL;
		return ERR_UNCONFIGURED;
	}
	r_call_error.error = Callable::CallError::CALL_OK;
	return node->rpcp(p_peer_id, method, p_arguments, p_argcount);
}