### 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)

#ifdef DEBUG_ENABLED
								if (value.get_type() != Variant::VECTOR2) {
									ERR_PRINT("Position key at time " + rtos(p_time) + " in Animation Track '" + String(pa->owner->path) + "' not of type Vector2(). Animation '" + a->get_name() + "' at node '" + get_path() + "'.");
								}
#endif
								static_cast<Node2D *>(pa->object)->set_position(value);
							} break;
							case SP_NODE2D_ROT: {
#ifdef DEBUG_ENABLED
								if (value.is_num()) {
									ERR_PRINT("Rotation key at time " + rtos(p_time) + " in Animation Track '" + String(pa->owner->path) + "' not numerical. Animation '" + a->get_name() + "' at node '" + get_path() + "'.");
								}
#endif
								static_cast<Node2D *>(pa->object)->set_rotation((double)value);
							} break;
							case SP_NODE2D_SCALE: {
#ifdef DEBUG_ENABLED
								if (value.get_type() != Variant::VECTOR2) {
									ERR_PRINT("Scale key at time " + rtos(p_time) + " in Animation Track '" + String(pa->owner->path) + "' not of type Vector2()." + a->get_name() + "' at node '" + get_path() + "'.");
								}
#endif
								static_cast<Node2D *>(pa->object)->set_scale(value);
							} break;
						}
					}
				}
			} break;
			case Animation::TYPE_METHOD: {
#ifdef TOOLS_ENABLED
				if (!can_call) {