Dask Traefik Proxy Exposed as ClusterIP. ----------- Separate Traefik2 Ingress Points to the Traefik Proxy Service

**What happened**:
Set dask service type to be ClusterIP
```
service:
type: ClusterIP
annotations: {}
spec: {}
ports:
web:
port: 80
nodePort: null
tcp:
# The port TCP requests will be served on. Set to `web` to share the
# web service port
port: web
nodePort: null
```
From the Client side tried to create a cluster and then get a client.

```
Timed out trying to connect to gateway://common-dask-test.int.somename.com:80/dask-common-test.5cdfc65644e644b08eae895132d63caa after 30 s
```

**What you expected to happen**:
Get a client reference back.
**Minimal Complete Verifiable Example**:

```python
from dask_gateway import Gateway
from dask_gateway.auth import BasicAuth
auth = BasicAuth(username='', password='samepassissetinthehelmchartsimplepassword')
g = Gateway('http://common-dask-test.somename.com', auth=auth)
c = g.new_cluster(shutdown_on_close=False)
client = c.get_client()
```

**Anything else we need to know?**:
Dask is installed using Helm Chart: https://github.com/dask/dask-gateway/tree/main/resources
```
RELEASE=dask-gateway-test
NAMESPACE=data-common-test
VERSION=0.9.0

helm upgrade --install \
--namespace $NAMESPACE \
--version $VERSION \
--values ./overrides-values.yaml \
$RELEASE \
daskgateway/dask-gateway
```
Ingress Exposing the traefik proxy service
```
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: traefik2
name: traefik-common-dask-gateway
namespace: dask-common-dev
spec:
rules:
- host: common-dask-test.dev.somedomain.com
http:
paths:
- path: /
backend:
serviceName: traefik-dask-common-test-dask-gateway
servicePort: 80
```
**Environment**:
K8s. 1.17 EKS

- Dask version:
-

```
dask==2021.7.2
dask-gateway==0.9.0
distributed==2021.7.2
```
On both dask cluster image and the local client.
- Python version: 3.10
- Operating System: Linux
- Install method (conda, pip, source): pip