Extra padding around the overflow menu for WC table

[dianasanborn]

The extra padding around the overflow menu is causing the small and xs rows to be taller than inteded.

Small example: https://web-components.carbondesignsystem.com/?path=/story/components-datatable-toolbar--playground&args=size:sm
XS example: https://web-components.carbondesignsystem.com/?path=/story/components-datatable-toolbar--playground&args=size:xs