docs(deprecated Table): remove old css prefix from md (#12623)

Hides empty CSS variables table on deprecated docs tab.

Author: kmcfaul

packages/react-table/src/deprecated/components/Table/examples/Table.md

@@ -1,6 +1,5 @@
 ---
 id: Table
-cssPrefix: pf-c-table
 section: components
 propComponents: ['Table', 'TableHeader', 'TableBody', 'ISortBy']
 ouia: true