### 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(p_xfade < 0);
	xfade_time = p_xfade;
	emit_changed();
}
float AnimationNodeStateMachineTransition::get_xfade_time() const {
	return xfade_time;
}
void AnimationNodeStateMachineTransition::set_xfade_curve(const Ref<Curve> &p_curve) {
	xfade_curve = p_curve;
}
Ref<Curve> AnimationNodeStateMachineTransition::get_xfade_curve() const {
	return xfade_curve;
}
void AnimationNodeStateMachineTransition::set_reset(bool p_reset) {
	reset = p_reset;
	emit_changed();
}
bool AnimationNodeStateMachineTransition::is_reset() const {
	return reset;
}
void AnimationNodeStateMachineTransition::set_priority(int p_priority) {
	priority = p_priority;
	emit_changed();
}
int AnimationNodeStateMachineTransition::get_priority() const {
	return priority;
}
void AnimationNodeStateMachineTransition::_bind_methods() {