Refactor ability to shift+TAB from table cell

[kolaps33]

Bug Report

With the following PR
#2147

there is coming the workaround about ability to shift tab from table cell, as well from table header cell and from table content cel.

actionHandlers = {
    unsetRowTabbable: e => {
      this.rowRef.current.setAttribute('tabindex', '-1')

The same issue is observed as well for focuszone:
https://developer.microsoft.com/en-us/fabric#/controls/web/focuszone
Example:
Nesting FocusZones in list rows
Navigate to the cell and then press shift+TAB. Focus goes on the row not away from the list (in our case table).

In our table case it is even more complicated as in the table header row we use

  shouldFocusInnerElementWhenReceivedFocus: true,

what it means that without the workaround user is not able to shift+TAB at all.