feat(viz): add option to add labels to web service (#13305)

Problem
There is no option to add labels to the dashboard service (web) specifically
for example, the use case of service mirror the dashboard service to make it accessible in another cluster needs the label:

```
mirror.linkerd.io/exported: 'true'
```

Solution
Add option to add labels to dashboard service only 

Validation
Run helm templates with couple of use cases to verify it adds new properties while not overwrite others.

I agree to the DCO for all the commits in this PR.

Signed-off-by: Alex Leong <[email protected]>
Co-authored-by: omer nitzan <[email protected]>
Co-authored-by: Alex Leong <[email protected]>

charts/linkerd2-cni/README.md

@@ -68,4 +68,4 @@ Kubernetes: `>=1.22.0-0`
 | useWaitFlag | bool | `false` | Configures the CNI plugin to use the -w flag for the iptables command |
 
 ----------------------------------------------
-Autogenerated from chart metadata using [helm-docs v1.12.0](https://github.com/norwoodj/helm-docs/releases/v1.12.0)
+Autogenerated from chart metadata using [helm-docs v1.14.2](https://github.com/norwoodj/helm-docs/releases/v1.14.2)

viz/charts/linkerd-viz/README.md

@@ -86,8 +86,9 @@ Kubernetes: `>=1.22.0-0`
 | dashboard.resources.memory.limit | string | `nil` | Maximum amount of memory that web container can use |
 | dashboard.resources.memory.request | string | `nil` | Amount of memory that the web container requests |
 | dashboard.restrictPrivileges | bool | `false` | Restrict the Linkerd Dashboard's default privileges to disallow Tap and Check |
-| dashboard.service | object | `{"annotations":{}}` | dashboard service configuration |
+| dashboard.service | object | `{"annotations":{},"labels":{}}` | dashboard service configuration |
 | dashboard.service.annotations | object | `{}` | Additional annotations to add to dashboard service |
+| dashboard.service.labels | object | `{}` | Additional labels to add to dashboard service |
 | defaultGID | int | `2103` | GID for all the viz components |
 | defaultImagePullPolicy | string | `"IfNotPresent"` | Docker imagePullPolicy for all viz components |
 | defaultLogFormat | string | `"plain"` | Log format (`plain` or `json`) for all the viz components. |

viz/charts/linkerd-viz/templates/web.yaml

@@ -12,6 +12,7 @@ metadata:
     component: web
     namespace: {{.Release.Namespace}}
     {{- with .Values.commonLabels }}{{ toYaml . | trim | nindent 4 }}{{- end }}
+    {{- with .Values.dashboard.service.labels }}{{ toYaml . | trim | nindent 4 }}{{ end }}
   annotations:
     {{ include "partials.annotations.created-by" . }}
     {{ with .Values.dashboard.service.annotations }}{{ toYaml . | trim | nindent 4 }}{{ end }}

viz/charts/linkerd-viz/values.yaml

@@ -405,6 +405,8 @@ dashboard:
   service:
     # -- Additional annotations to add to dashboard service
     annotations: {}
+    # -- Additional labels to add to dashboard service
+    labels: {}
 
 namespaceMetadata:
   image: