Vertically centres landscape avatars those cannot fill up parent height.

app/assets/javascripts/groups/components/group_item.vue

@@ -100,7 +100,7 @@ export default {
       </div>
       <div
         :class="{ 'content-loading': group.isChildrenLoading }"
-        class="avatar-container s24 d-none d-sm-block"
+        class="avatar-container s24 d-none d-sm-flex"
       >
         <a
           :href="group.relativePath"

app/assets/stylesheets/framework/avatar.scss

@@ -104,6 +104,7 @@
 
   a {
     width: 100%;
+    height: 100%;
     display: flex;
   }