### Godot version

4.2 RC2

### System information

Any

### Issue description

AnimationMixer separates the accuracy of how discrete keys are retrieved when seeking between internal seeking and external seeking. FYI: https://github.com/godotengine/godot/pull/80708.

Since AnimationPlayer currently treats everything as an internal seek, so it needs to propagate the external seek information.

### Steps to reproduce

Seek AnimationTrackEditor

### Minimal reproduction project

[gd_anim_unittest_1.zip](https://github.com/godotengine/godot/files/13492063/gd_anim_unittest_1.zip)

BlendKey bk;
	bk.from = p_animation1;
	bk.to = p_animation2;
	if (blend_times.has(bk)) {
		return blend_times[bk];
	} else {
		return 0;
	}
}
void AnimationPlayer::get_argument_options(const StringName &p_function, int p_idx, List<String> *r_options) const {
	String pf = p_function;
	if (p_idx == 0 && (p_function == "play" || p_function == "play_backwards" || p_function == "has_animation" || p_function == "queue")) {
		List<StringName> al;
		get_animation_list(&al);
		for (const StringName &name : al) {
			r_options->push_back(String(name).quote());
		}
	}
	Node::get_argument_options(p_function, p_idx, r_options);
}
void AnimationPlayer::_animation_removed(const StringName &p_name, const StringName &p_library) {