### 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)

to_play.push_back(first_key);
						}
					}
					a->track_get_key_indices_in_range(i, p_time, p_delta, &to_play, p_looped_flag);
					if (to_play.size()) {
						idx = to_play.back()->get();
					}
				}
				if (idx < 0) {
					continue;
				}
				
				Ref<AudioStream> stream = a->audio_track_get_key_stream(i, idx);
				if (stream.is_valid()) {
					double start_ofs = a->audio_track_get_key_start_offset(i, idx);
					double end_ofs = a->audio_track_get_key_end_offset(i, idx);
					double len = stream->get_length();
					if (aa->object->call(SNAME("get_stream")) != aa->audio_stream) {
						aa->object->call(SNAME("set_stream"), aa->audio_stream);
						aa->audio_stream_playback.unref();
						if (!playing_audio_stream_players.has(asp)) {
							playing_audio_stream_players.push_back(asp);
						}
					}
					if (!aa->object->call(SNAME("is_playing"))) {
						aa->object->call(SNAME("play"));
					}
					if (!aa->object->call(SNAME("has_stream_playback"))) {
						aa->audio_stream_playback.unref();
						continue;