### Godot version

v4.1.rc2.official [46424488e]

### System information

Godot v4.1.rc2 - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3060 (NVIDIA; 31.0.15.3623) - AMD Ryzen 7 5700G with Radeon Graphics (16 Threads)

### Issue description

When setting the AnimationTree to active, Godot crashes.

### Steps to reproduce

https://github.com/godotengine/godot/assets/46705245/dbe5eb81-1357-43e8-ac80-a4eb97eea9fc

### Minimal reproduction project

[Crash.zip](https://github.com/godotengine/godot/files/11945826/Crash.zip)

ERR_FAIL_COND_V_EDMSG(!states.has(p_name), Ref<AnimationNode>(), String(p_name) + " is not found current state.");
	return states[p_name].node;
}
StringName AnimationNodeStateMachine::get_node_name(const Ref<AnimationNode> &p_node) const {
	for (const KeyValue<StringName, State> &E : states) {
		if (E.value.node == p_node) {
			return E.key;
		}
	}
	ERR_FAIL_V(StringName());
}
void AnimationNodeStateMachine::get_child_nodes(List<ChildNode> *r_child_nodes) {
	Vector<StringName> nodes;
	for (const KeyValue<StringName, State> &E : states) {
		nodes.push_back(E.key);
	}
	nodes.sort_custom<StringName::AlphCompare>();
	for (int i = 0; i < nodes.size(); i++) {
		ChildNode cn;
		cn.name = nodes[i];
		cn.node = states[cn.name].node;
		r_child_nodes->push_back(cn);
	}
}
bool AnimationNodeStateMachine::has_node(const StringName &p_name) const {