Update source/handbook/finance/authorization-matrix/index.html.md

Why is this change being made?

To add an exception to section 6 for Benefit and Payroll Related Expenses as those are recurring operating costs approved in plan.

cc @shoneycutt @daleb04 @a.hansen

How will this merge request impact page speed?

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what