LP#2009281 Duplicate Entries in Retrieve Recent Patrons Grid

LP#2009281 Duplicate Entries in Retrieve Recent Patrons Grid

ID is a string when pulled from the route and a number when
pulled from patron search, so the type mismatch causes the
duplicate check to fail. This converts the ID to a number
before appending it to the array of recent patrons.

To test:
1. Set "Number of Retrievable Recent Patrons" setting to 2
2. Load a patron from Patron Search
3. Go to Circulation->Retrieve Last Patron
4. Go to Circulation->Retrieve Recent Patrons
   - note that the patron is not duplicated

Signed-off-by: Dan Briem <dbriem@wlsmail.org>