NOTE: this could be done only when all tabs in Item Selector are migrated to metal/react.
NOTE 2: Remove the extra event introduced in and .es.js_. It won't be neccessary because we can now use the previous event if it is a single selection. Anyway, check if there will be a breaking change or not.
NOTE 3: The views are the ones who know if it is a single selection or multiple. ItemSelectorDialog does not know it for now. Also, it is possible that one view has single selection and other multiple , because a list of desired return types are set. We can add a method `isMultiple()` in that will be set to false as default. If there is any view that allows multiple selection, should put this value to true. Then ItemSelectorDialog should use this value to show or not the footer.
Given an item selector where only single elements can be selected
When the user access them
Then the footer does not appear and all the buttons are placed in the top bar