Issue description:
The table copy/pasted from MS office is not sortable even making the first row sortable.

Repro:

• Create a little Table in Excel
• Copy it
• Go to Confluence and paste it into the editor
• Mark the first row as Header
• Save the page
• Check if the table has the sorting feature
  -> It has not

Workaround:

• Go to the editor again
• Cut out the (unsortable) table
• Paste it again
• Mark the first row as Header
• Save the page
  -> Now the table is sortable

If that does not work, please install the The confluence source editor, then edit the page to:

1. Remove the row "<colgroup> <col/> <col/> <col/> <col/> <col/> <col/> <col/> <col/> <col/> <col/> <col/> <col/> </colgroup>"
2. Replace all "td" tag to "th" tag for the first row of the table. For example, the column name "Number" will need to change from "<td>Number</td>" to "<th>Number</th>".