Allow user to link an invoice line to a PO line after the invoice line has been created

Purpose: Allow user to review an invoice created from an imported EDIFACT file, identify any invoice lines that were not linked to PO lines, then search and link those invoice lines to the correct PO lines

User story statement(s):

As a librarian who has imported an EDIFACT invoice
I want to be able to identify invoice lines that were not linked to PO lines and search/link them to the correct PO lines
So that all invoice lines are connected to the appropriate PO lines
NOTE: Per conversation with Acq and Data Import SMEs, no scenario was identified where an invoice line would not be linked to a PO line.

Scenarios:

1. Scenario:
   • Given an invoice IS NOT in "Approved" or "Paid" status
   • When creating or editing invoice line(s)
   • Then user can use POL look-up to link a POL
   • 
2. Scenario:
   • Given user is creating or editing invoice line
   • When user clicks POL look-up
   • Then POL lookup plugin is displayed
   • AND user can search and click on a POL (Note user CANNOT select more than one POL)
   • 
3. Scenario:
   • Given the user has created an invoice manually or via import
   • And the invoice status = Open or Reviewed (but not Approved or Paid)
   • When activating POL look-up
   • Then the user can choose a POL and it will be linked to the invoice line; if there is an existing POL linked to the invoice line, the newly-selected POL will replace the previous POL
   • AND IF there is an existing POL linked to the invoice line, update ONLY the invoice line description (title) and fund distribution with the information from the newly-linked POL, but not the quantity or price
4. Scenario
   • Given there is a POL number in the POL field
   • When the user clicks the "x" to clear the number
   • Then the UUID of the POL is removed
   • AND no of the other invoice line data is changed

Note: The previous relationship between the invoice line and POL should be cleaned up when a user is changing the link to a new POL. i.e. any link between encumbrance and the invoice line and PO and Invoice etc. These links would be made with the new POL that is linked to the invoice line.