Reset Dask worker to use TCP even if it was configured to use TLS in yaml file

**Describe the issue**:
The DASK operator reset to use TCP even if it was configured to use TLS

```yaml
- name: DASK_SCHEDULER_ADDRESS
value: tls://scheduler.join.svc.cluster.local:8786
- name: DASK_TEMPORARY_DIRECTORY
value: /tmp
- name: DASK_WORKER_NAME
value: default-worker-6a9c9e4f94
- name: DASK_SCHEDULER_ADDRESS
value: tcp://scheduler.join.svc.cluster.local:8786
```

The code to append the config is here: https://github.com/dask/dask-kubernetes/blob/fa7255b95e686025fd818f718b83635ff9424769/dask_kubernetes/operator/controller/controller.py#L156

**Minimal Complete Verifiable Example**:

```python
# Put your MCVE code here
```

**Anything else we need to know?**:

**Environment**:

- Dask version:
- Python version:
- Operating System:
- Install method (conda, pip, source):