Enable new cluster list design

What does this MR do?

The current Cluster Index View has the following code:

- if Feature.enabled?(:clusters_list_redesign)
      #js-clusters-list-app{ data: { endpoint: clusterable.index_path(format: :json) } }
    - else
      .clusters-table.js-clusters-list
        .gl-responsive-table-row.table-row-header{ role: "row" }
          .table-section.section-60{ role: "rowheader" }
            = s_("ClusterIntegration|Kubernetes cluster")
          .table-section.section-30{ role: "rowheader" }
            = s_("ClusterIntegration|Environment scope")
          .table-section.section-10{ role: "rowheader" }
        - @clusters.each do |cluster|
          = render "cluster", cluster: cluster.present(current_user: current_user)
      = paginate @clusters, theme: "gitlab"

Feature.enabled?(:clusters_list_redesign) is part of a redesign where we:

• Refactor/Move the cluster list from haml to vue
• Add additional columns to the cluster table. (See related Epic: &2666 (closed))

This MR will

• Enable the feature flag by default. Customers will now see the vue cluster table instead of the haml cluster table

Future MRs will:

• Assuming there are no bugs, a follow-up MR will completely remove the feature flag. It will also remove the haml views: !42849 (merged)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #220182 (closed)