Use pkg.vendor as provider

In the Agreement UI "EResourceProvider" uses the following fields:

• _object.pti.platform.name -> for PCI from internal KB
• _object.nominalPlatform.name -> for pkg from internal KB
• reference_object.provider -> for resources from external source (i.e. eHoldings)

Instead it should use:

• _object.pkg.vendor.name -> for PCI from internal KB
• _object.vendor.name -> for pkg from internal KB
• reference_object.provider -> for resources from external source (i.e. eHoldings)

This will correct the display of the provider information in the Agreement Line MCL (which currently displays Platform information for internal KB resources and Provider for external source resources)