add individual examples for data-table icon and header scanarios

ui/components/data-tables/advanced/example.jsx

@@ -261,15 +261,48 @@ export let states = [

export let examples = [
  {
    id: 'header-and-cell-icon',
    label: 'Header and Cell Icon',
    id: 'header-icon-menu-button',
    label: 'Header Icon and Menu Button',
    element: (
      <Table>
        <Thead
          actionableMode
          columns={columns}
          columnsWithEinstein={['Confidence']}
          hasMenus
        />
        <tbody>
          {_.times(rows.length, i => (
            <AdvancedDataTableTr key={i} index={i + 1} {...rows[i]} />
          ))}
        </tbody>
      </Table>
    )
  },
  {
    id: 'header-menu-button',
    label: 'Header Menu Button',
    element: (
      <Table>
        <Thead actionableMode columns={columns} hasMenus />
        <tbody>
          {_.times(rows.length, i => (
            <AdvancedDataTableTr key={i} index={i + 1} {...rows[i]} />
          ))}
        </tbody>
      </Table>
    )
  },
  {
    id: 'cell-icon',
    label: 'Cell Icon',
    element: (
      <Table>
        <Thead
          actionableMode
          className="slds-has-button-menu"
          columns={columns}
        />
        <tbody>
          {_.times(rows.length, i => (
            <AdvancedDataTableTr key={i} index={i + 1} {...rows[i]} hasScores />