(Table): wrap Icon with container, following docs

Author: msmx-mnakagawa

src/scripts/Table.tsx

@@ -186,6 +186,7 @@ export const TableHeaderColumn: FC<TableHeaderColumnProps> = (props) => {
           <span className='slds-assistive-text'>Sort </span>
           {cellContent}
           <Icon
+            container
             className='slds-is-sortable__icon'
             textColor='default'
             size='x-small'