### 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)

b.blend_left = CMP_EPSILON; 
		}
		
		
		_process_playback_data(b.data, p_delta, b.blend_left, false, false);
	}
	for (List<Blend>::Element *&E : to_erase) {
		c.blend.erase(E);
	}
}
bool AnimationPlayer::_blend_pre_process(double p_delta, int p_track_count, const HashMap<NodePath, int> &p_track_map) {
	if (!playback.current.from) {
		_set_process(false);
		return false;
	}
	tmp_from = playback.current.from->animation->get_instance_id();
	end_reached = false;
	end_notify = false;
	bool started = playback.started; 
	if (playback.started) {
		playback.started = false;
	}
	AnimationData *prev_from = playback.current.from;
	_blend_playback_data(p_delta, started);
	if (prev_from != playback.current.from) {
		return false; 
	}
	return true;
}
void AnimationPlayer::_blend_post_process() {