Can't install provider from private registry

### What happened?
When moving original image from xpkg.upbound.io to an internal repository and installing the provider, the provider fails to start, since it's referencing the controller image in `package/crossplane.yaml` (even though the provider is mono-image and injects runtime on build)

### How can we reproduce it?
Try to run the provider on a k8s cluster with no access to public repos.

### What environment did it happen in?
Crossplane version: all

If
```yaml
controller:
image: xpkg.upbound.io/linode/provider-ceph:v0.0.40
```
gets removed from `package/crossplane.yaml`, provider will default to start embedded runtime :)

Start with package/crossplane.yaml and reproduce the installation on a Kubernetes cluster without access to public registries. Verify how the controller image reference affects startup for the mono-image provider, and confirm the provider starts successfully from an internal registry using its embedded runtime.

Written by the indexing model from the issue text.