Show the world icon for open groups in the groups dropdown and

private group icon otherwise.

Fixes https://github.com/hypothesis/product-backlog/issues/513

src/sidebar/templates/group-list.html

@@ -5,7 +5,7 @@
         dropdown-toggle
         data-toggle="dropdown"
         role="button"
-        ng-switch on="vm.groups.focused().public"
+        ng-switch on="vm.groups.focused().type == 'open'"
         title="Change the selected group">
     <img class="group-list-label__icon group-list-label__icon--third-party"
          ng-src="{{ vm.thirdPartyGroupIcon }}"
@@ -26,7 +26,7 @@
       <div ng-class="{'group-item': true, selected: group.id == vm.groups.focused().id}"
            ng-click="vm.focusGroup(group.id)">
         <!-- the group icon !-->
-        <div class="group-icon-container" ng-switch on="group.public">
+        <div class="group-icon-container" ng-switch on="group.type == 'open'">
           <img class="group-list-label__icon group-list-label__icon--third-party"
                ng-src="{{ vm.thirdPartyGroupIcon }}"
                ng-if="vm.thirdPartyGroupIcon"