### 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)

#include "animation_player.h"
#include "animation_player.compat.inc"
#include "core/config/engine.h"
#include "scene/scene_string_names.h"
bool AnimationPlayer::_set(const StringName &p_name, const Variant &p_value) {