Add the LAC.YP field to the Students Extended API endpoint.

The YP field is used as part of the LTEL indicator in the LCAP dashboard (along with STU.LF)
https://support.aeries.com/support/solutions/articles/14000072084-chart-of-lcap-indicators

This is NOT the same information as is provided by the state import of LTEL indicators contained in the LAC.LT and LAC.YEL fields, which are currently included in the extended endpoint.