Maintain item status date even if item record is edited

Purpose: The item status date for an item is currently updated when the item's status changes, as well as when users edit fields in the item record. Instead, the item status date should only show when the item status was last updated.

Story: As a resource access staff member, I want to see when an item was assigned a particular status, so that I can assess an item's likely whereabouts and when it was last used.

1. Scenario
   • Given an item that has the item status Missing, with item status date X, and pending changes in the Edit item record screen
   • When the user clicks Update item
   • Then save changes to the item record, and maintain item status date as X
2. Scenario
   • Given an item that has the item status Available, with item status date X, and pending changes in the Edit item record screen
   • When the user clicks Update item at time Y
   • Then save changes to the item record, and maintain item status date as X
3. Scenario
   • Given an item that has the item status In transit, with item status date X, and pending changes in the Edit item record screen
   • When the user clicks Update item at time Y
   • Then save changes to the item record, and maintain item status date as X
4. Scenario
   • Given an item that has the item status Checked out, with item status date X, and pending changes in the Edit item record screen
   • When the user clicks Update item at time Y
   • Then save changes to the item record, and maintain item status date as X