Show cluster health badge in Environment index page

What does this MR do and why?

This MR adds the health label to the Environments page (Kubernetes integration section) according to the design.

This MR provides the feature overview.

The cluster is defined as 'healthy' if all the resources (pods and workload types) are loaded with no failed items. The cluster can still be 'healthy' if the request failed as we don't know the status of the resources and we already show an error message for the user to consider.

The cluster is defined as 'unhealthy` if any of the resources (pods and workload types) have failed items.

Screenshots or screen recordings

Healthy	Unhealthy

How to set up and validate locally

1. Enable feature flags:

      Feature.enable(:environment_settings_to_graphql)

      Feature.enable(:kas_user_access)

      Feature.enable(:kas_user_access_project, Project.find(<your-project-id>))

      Feature.enable(:expose_authorized_cluster_agents)

2. Enable KAS on your GDK (steps 1-2 from the guide).

3. Visit the Project -> Infrastructure -> Kubernetes clusters page and create an agent following the instruction from the modal.

   • Select the "Connect a cluster" button
   • The modal should pop up
   • In the modal select "Select an agent or enter a name to create new"
   • You probably won't have any configured agents to show up in the list, create a new one by typing the name of your choice
   • The button should appear at the bottom of the list saying "Create agent: <your-agent-name>"
   • Select the button and click "Register" in the next view.
   • Save the token to use it in the next point.

4. Please follow points 3-8 from the guide and then the (Optional) Deploy the GitLab Agent (agentk) with k3d section to create a local cluster and connect your agent with the cluster.

5. Add the following configuration files inside your project, commit the following on the default branch:

   1. .gitlab/agents/<your-agent-name>/config.yaml:

      gitops:
        manifest_projects:
        - id: <your-group>/<your-project>
      user_access:
        access_as: 
          agent: {}
        projects:
        - id: <your-group>/<your-project>

   2. namespace.yaml

      apiVersion: v1
      kind: Namespace
      metadata:
        name: demo-k8s-app

   3. app.yaml

      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: app
        namespace: demo-k8s-app
      spec:
        replicas: 2
        selector:
          matchLabels:
            name: app
        template:
          metadata:
            labels:
              name: app
          spec:
            containers:
              - name: app
                image: learnk8s/first-k8s-app:1.0.0
                ports:
                  - containerPort: 80
                imagePullPolicy: Always
      ---
      apiVersion: v1
      kind: Service
      metadata:
        name: app
      spec:
        selector:
          name: app
        ports:
          - port: 8080
            targetPort: 80
      ---
      apiVersion: networking.k8s.io/v1
      kind: Ingress
      metadata:
        name: app
        annotations:
          nginx.ingress.kubernetes.io/rewrite-target: /
      spec:
        rules:
          - http:
              paths:
                - path: /second
                  pathType: Prefix
                  backend:
                    service:
                      name: app
                      port:
                        number: 8080

6. Visit the Environments page:

   • Project -> Operate -> Environments if the new navigation is enabled
   • Project -> Deployments -> Environments if the new navigation is not enabled

7. Create/Edit an environment using the UI, select the agent created in the previous steps

8. Navigate to the Environments page, toggle the environment, wait for the Kubernetes overview to appear and verify the health label

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Review progress:

• frontend developer review
• frontend maintainer review

Related to #390769 (closed)