message: trap keyboard focus within the dropdown when open
  should fulfil behaviour described in
diff: @@ -2,6 +2,7 @@ import Component from '@glimmer/component';
  //@ts-expect-error glint does not think hash is consume but it is
  import { hash } from '@ember/helper';
  import cn from '@cardstack/boxel/helpers/cn';
  +import focusTrap from 'ember-focus-trap/modifiers/focus-trap';
  import BasicDropdown from 'ember-basic-dropdown/components/basic-dropdown'
  @@ -25,7 +26,10 @@ class BoxelDropdown extends Component<Signature> {
  <dd.Trigger ...attributes>
  {{yield to="trigger"}}
  </dd.Trigger>
  - <dd.Content class={{cn "boxel-dropdown__content" @contentClass}}>
  + <dd.Content
  + class={{cn "boxel-dropdown__content" @contentClass}}
  + {{focusTrap isActive=dd.isOpen focusTrapOptions=(hash onDeactivate=dd.actions.close allowOutsideClick=true)}}
  + >
  {{yield (hash close=dd.actions.close) to="content"}}
  </dd.Content>
  </BasicDropdown>
  