feat(ui): display an error message when trying to remove a network with active endpoints

app/components/networks/networksController.js

@@ -45,9 +45,14 @@ function ($scope, Network, Messages, errorMsgFilter) {
       if (network.Checked) {
         counter = counter + 1;
         Network.remove({id: network.Id}, function (d) {
+          var error = errorMsgFilter(d);
+          if (error) {
+            Messages.send("Error", "Unable to remove network with active endpoints");
+          } else {
             Messages.send("Network deleted", network.Id);
             var index = $scope.networks.indexOf(network);
             $scope.networks.splice(index, 1);
+          }
           complete();
         }, function (e) {
           Messages.error("Failure", e.data);