Tidy token list for staff slips

Context:
Long term solution includes an expansion to tokens available, and it is defined by several UI and back end stories, linked below.

The token list available in the UI for templates does not match the tokens that actually work for patron notices.

Here's what's available through the UI now:

More item tokens are being added and addressed through UICIRC-189, so this story specifically addresses renaming the current list to be aligned with pattern used for patron notices.

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Story:
Given any type of staff slip
When a FOLIO operator tries to create a new one and/or edit one and clicks on the token icon "{ }" in the template
Then the following token options should appear in a dropdown:

• requester.firstName (instead of Requester first name)
• requester.lastName (instead of Requester last name)
• requester.barcode (instead of Requester barcode)
• request.holdShelfExpirationDate (instead of hold expiration)
• item.title (instead of item title)
• item.barcode (instead of item barcode)
• transationID (instead of transaction Id)