Show system as source in loan action table when lost item fees are paid

Purpose: Once the patron has paid for the item (or the associated fines have otherwise been taken care of - for example, if the library waives them), the loan can be closed.

This action is mostly being shown correctly in the loan action history, but does not have a source listed. This story is to address that (in bold, below)

Scenarios

1. Scenario
   • Given an item with the status Lost and paid
   • When viewing loan details for the loan that was declared lost
   • Then the last row of the action table should be the following
     • Action date: <date the loan was closed>
     • Action: Closed loan
     • Due date: <Due date at time loan was closed>
     • Item status: Lost and paid
     • Source: System
     • Comments: <None>

Notes: split from UIU-1204
Notes: Updated 2020-06-15 based on RA SIG discussion