message: add more padding to bottom of child brige widget
diff: <div class="flex-column d-flex align-items-stretch h-100 w-100 pb-1 overflow-auto no-scrollbars">
  - <div style="cursor: move;" class="drag-handler pl-2 pt-1 pb-1 pr-2">
  + <div style="cursor: move;" class="drag-handler pl-2 pt-1 pb-2 pr-2">
  {{ 'child_bridge.label_child_bridges' | translate }}
  </div>
  <div class="d-flex flex-wrap w-100 pl-2 pr-2">
  