### Godot version

4.0.beta13

### System information

Windows 10

### Issue description

When you call the `seek()` function without a current animation it outputs `Condition "!playback.current.from" is true.` to the debugger.

I was getting the error above whenever I would call `stop()` on an AnimationPlayer when it didn't have a playing animation. I realized that `stop()` also calls the `seek()` function.

I would expect the `seek()` and `stop()` functions to just do nothing, instead of throwing errors, if there isn't a current animation, or at least show an error that says that there is no animation to seek/stop.

This is the same issue that was described here: [#6122](https://github.com/godotengine/godot/issues/6122)

### Steps to reproduce

- Create an AnimationPlayer node.
- Don't have it play any animations.
- Call the `seek()` function.

### Minimal reproduction project

[seek_issue.zip](https://github.com/godotengine/godot/files/10442071/seek_issue.zip)

int at_pos = -1;
	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
		if (animation_libraries[i].name == p_name) {
			at_pos = i;
			break;
		}
	}
	ERR_FAIL_COND(at_pos == -1);
	animation_libraries[at_pos].library->disconnect(SNAME("animation_added"), callable_mp(this, &AnimationPlayer::_animation_added));
	animation_libraries[at_pos].library->disconnect(SNAME("animation_removed"), callable_mp(this, &AnimationPlayer::_animation_removed));
	animation_libraries[at_pos].library->disconnect(SNAME("animation_renamed"), callable_mp(this, &AnimationPlayer::_animation_renamed));
	animation_libraries[at_pos].library->disconnect(SNAME("animation_changed"), callable_mp(this, &AnimationPlayer::_animation_changed));
	stop();
	animation_libraries.remove_at(at_pos);
	_animation_set_cache_update();
	notify_property_list_changed();
}
void AnimationPlayer::rename_animation_library(const StringName &p_name, const StringName &p_new_name) {
	if (p_name == p_new_name) {
		return;
	}
#ifdef DEBUG_ENABLED
	ERR_FAIL_COND_MSG(String(p_new_name).contains("/") || String(p_new_name).contains(":") || String(p_new_name).contains(",") || String(p_new_name).contains("["), "Invalid animation library name: " + String(p_new_name) + ".");
#endif
	bool found = false;
	for (AnimationLibraryData &lib : animation_libraries) {
		ERR_FAIL_COND_MSG(lib.name == p_new_name, "Can't rename animation library to another existing name: " + String(p_new_name));
		if (lib.name == p_name) {
			found = true;