Remove "project namespace" from cluster index page

app/views/clusters/clusters/_cluster.html.haml

 .gl-responsive-table-row
-  .table-section.section-30
+  .table-section.section-60
     .table-mobile-header{ role: "rowheader" }= s_("ClusterIntegration|Kubernetes cluster")
     .table-mobile-content
       = link_to cluster.name, cluster.show_path
   .table-section.section-30
     .table-mobile-header{ role: "rowheader" }= s_("ClusterIntegration|Environment scope")
     .table-mobile-content= cluster.environment_scope
-  .table-section.section-30
-    .table-mobile-header{ role: "rowheader" }= s_("ClusterIntegration|Project namespace")
-    .table-mobile-content= cluster.platform_kubernetes&.actual_namespace
   .table-section.section-10
     .table-mobile-header{ role: "rowheader" }
     .table-mobile-content

app/views/clusters/clusters/index.html.haml

@@ -13,12 +13,10 @@
       = render 'clusters/clusters/buttons'
     .ci-table.js-clusters-list
       .gl-responsive-table-row.table-row-header{ role: "row" }
-        .table-section.section-30{ role: "rowheader" }
+        .table-section.section-60{ role: "rowheader" }
           = s_("ClusterIntegration|Kubernetes cluster")
         .table-section.section-30{ role: "rowheader" }
           = s_("ClusterIntegration|Environment scope")
-        .table-section.section-30{ role: "rowheader" }
-          = s_("ClusterIntegration|Project namespace")
         .table-section.section-10{ role: "rowheader" }
       - @clusters.each do |cluster|
         = render "cluster", cluster: cluster.present(current_user: current_user)