Can't patch XR metadata

### What happened?

Status propagation works
```
apiVersion: example.crossplane.io/v1beta1
kind: XR
status:
dummy: cool-status
```

But metadata propagation does not.
```
apiVersion: example.crossplane.io/v1beta1
kind: XR
metadata:
annotation:
cool: annotation
```

### How can we reproduce it?

Try to set custom annotation for XR as in the example above. You will notice that annotation is not propagated to the XR

### What environment did it happen in?
Function version: v0.4.1