prevent long usernames or user emails from breaking mobile layout on admin/overview/users

app/assets/stylesheets/pages/admin.scss

@@ -79,10 +79,13 @@
     display: -webkit-flex;
     display: -ms-flexbox;
     display: flex;
+    white-space: nowrap;
   }
   .user-details {
     flex: 1 1 auto;
+    overflow: hidden;
+    padding-right: 8px;
   }
   .user-name {
@@ -90,6 +93,12 @@
     font-weight: 600;
   }
+  .user-name,
+  .user-email {
+    overflow: hidden;
+    text-overflow: ellipsis;
+  }
+
   .dropdown {
     .btn-block {
       margin-bottom: 0;