Restrict adjustment of budget's allowableEncumbrance and allowableExpenditures

Overview

Before allowing a user to adjust a budget's allowableEncumbrance and allowableExpenditure values, we need to make sure the new limits aren't already exceeded. If they are we must reject the update and return an appropriate error.

• If adjusting allowableEncumbrance, first check that the amount (encumbered + awaitingPayment) isn't already over the new value.
• If adjusting allowableExpenditures, first check that the amount (expended + awaitingPayment) isn't already over the new value.

if ((allocated * newAllowableEncumbrance) < (encumbrance + awaitingPayment) 
  reject
else 
  apply update

if ((allocated * newAllowableExpenditure) < (awaitingPayment + expended)) 
  reject
else 
  apply update

Acceptance Criteria

• The checks described above are put in place
• unit tests are updated
• API tests are updated