Request staff notes: Capture staff note when cancelling a request

User story:
As a FOLIO administrator who is cancelling a request
I want to be able to add a staff note in the cancellation popup to document reason for cancellation to my staff. 

Requirements

Requirement 1: Request Cancellation modal - Display an Additional information for staff field 

• Given I have accessed the Requests app
• When a request is cancelled (see Actions menu for open requests)
• Then the cancellation popup should include a new "Additional information for staff" field
  • Large text box
  • Character limit: 1500
  • Optional
  • Ghost text: "Enter staff only information about the cancellation (optional)

Requirement 2: View Cancelled - Request detail record: Display an Add a Additional information for staff field  

• Given the user enters a note in the "Additional information for staff" field on the request cancellation popup
• When the cancellation is confirmed
• Then the note will be saved
• AND on the View Request details : A new field called Additional information for staff displays below Cancellation reason field (see below mockup) 
• If no Staff note entered then do not display field.