registryMirrorConfiguration does not work with self-signed private docker registries.

**What happened**:
I am trying to provision an EKS-A cluster with bottlerocket nodes. I have a private docker registry configured with self-signed certificates. I have set the `registryMirrorConfiguration` section of the Cluster resource as documented.

```
registryMirrorConfiguration:
endPoint:
authenticate: true
caCertContent: |
-----BEGIN CERTIFICATE-----
MIIE....
```

When provisioning the cluster I get the following error

```bash
sudo eksctl anywhere create cluster --hardware-csv hardware.csv -f cluster.yaml'
Warning: The recommended number of control plane nodes is 3 or 5
Warning: The recommended number of control plane nodes is 3 or 5
Logging in to docker registry :443
Error: Error response from daemon: Get "https://:443/v2/": x509: certificate signed by unknown authority
```

**What you expected to happen**:
The eks-a cluster should be provisioned with insecure registries.

**How to reproduce it (as minimally and precisely as possible)**:
* Provision a private registry with self-signed certificates.
* In the EKSA cluster configuration add the `registryMirrorConfiguration` section with the required details.
* The certificate used in the EKSA cluster configuration is the same as used in a docker client.

**Anything else we need to know?**:
I am using the bottlerocket host OS for deploying the cluster.

**Environment**:
- EKS Anywhere Release: v0.14.2
- EKS Distro Release: 1.24

Start at the `registryMirrorConfiguration` handling used by `eksctl anywhere create cluster`, with attention to the Bottlerocket path and Docker registry login. Reproduce the self-signed registry setup from the issue using EKS Anywhere v0.14.2 and verify how `caCertContent` is passed. Done means the configured certificate is trusted and cluster provisioning succeeds without the x509 error.

Written by the indexing model from the issue text.