Display selected status of single title resources from eHoldings in Agreement Line

Purpose:
When an agreement line consists of a single title from eHoldings, the "Count" displays as "1", whereas when the agreement line consists of a package, the count displays as "X / Y" where X is the number of selected titles in the package and Y is the total number of titles in the package.

For consistency and better information the single title should use the same convention and either be 1 / 1 (title is selected) or 0 / 1 (title is not selected)

User story statement(s):

As a ERM librarian,
I want to see the same information for a single title in an agreement line as for a package
so that I can easily understand the information I am seeing

As a ERM librarian,
I want to see the if a title is 'selected' or not in eHoldings
so that I can check that titles are selected as I expect

Scenarios:

1. Scenario:
   • Given an agreement line linked to a single title in eHoldings
   • When that title is not selected in eHoldings
   • Then the "Count" should be 0 / 1
2. Scenario:
   • Given an agreement line linked to a single title in eHoldings
   • When that title is selected in eHoldings
   • Then the "Count" should be 1 / 1

The selection status of a title is available in the response from /eholdings/resources in `isSelected` property which we would need to grab on the backend (Entitlement.groovy) before we could display on the frontend