Fix padding on nuxeo-data-table-settings icon

When viewing a nuxeo-data-table with a small number of results (such that a scrollbar is not present), there is minimal right-side padding on the nuxeo-data-table-settings icon that makes it look cut-off on the right side.

Steps to reproduce:

1. In Web UI, create a Folderish document that has a nuxeo-results element in its View layout
2. Add a small number of documents (approx. 1-4) so that a scrollbar will not be displayed on viewing nuxeo-data-table
3. Switch the nuxeo-results mode to view the nuxeo-data-table and observe the nuxeo-data-table-settings icon at the top-right of the table

Expected result: there is sufficient padding toward the right of the nuxeo-data-table-settings icon to match the top-side padding.

Actual result: the right-side border of nuxeo-data-table nearly touches the nuxeo-data-table-settings icon and looks as if the table is cutting the icon off on the right side. (see attached images for reference)