### 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)

if (blend_times.has(bk)) {
				blend_time = blend_times[bk];
			} else {
				bk.from = c.current.from->name;
				bk.to = "*";
				if (blend_times.has(bk)) {
					blend_time = blend_times[bk];
				}
			}
		}
		if (p_custom_blend < 0 && blend_time == 0 && default_blend_time) {
			blend_time = default_blend_time;
		}
		if (blend_time > 0) {
			Blend b;
			b.data = c.current;
			b.blend_left = 1.0;
			b.blend_time = blend_time;
			c.blend.push_back(b);
		} else {
			c.blend.clear();
		}
	}
	if (get_current_animation() != p_name) {
		_clear_caches();
	}
	c.current.from = &animation_set[name];
	c.current.speed_scale = p_custom_scale;
	if (!end_reached) {
		playback_queue.clear();