Error spammed after rusty jetpack is given to enemies in simulacrum

No clue if it affected the enemies' usage of it, but enemies barely jump anyways so idk

```
[Error  : Unity Log] NullReferenceException: Object reference not set to an instance of an object
Stack trace:
LostInTransit.Items.RustyJetpack+RustyJetpackBehavior.FixedUpdate () (at <28a00f1eb42e44e1ae51859d463da4d9>:IL_000B)
```