### 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)

List<PropertyInfo> anim_names;
	for (const KeyValue<StringName, AnimationData> &E : animation_set) {
		HashMap<StringName, StringName>::ConstIterator F = animation_next_set.find(E.key);
		if (F && F->value != StringName()) {
			anim_names.push_back(PropertyInfo(Variant::STRING, "next/" + String(E.key), PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
		}
	}
	for (const PropertyInfo &E : anim_names) {
		p_list->push_back(E);
	}
	p_list->push_back(PropertyInfo(Variant::ARRAY, "blend_times", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
}
void AnimationPlayer::_notification(int p_what) {