Export of Agreement content as JSON does not use PCI coverage

Possibly related to ERM-385

On export of an Agreement (e.g. using https://folio-snapshot-okapi.aws.indexdata.com/erm/sas/f007a2f3-6cb0-48bf-8321-91e0f02dd126/export the export seems to use the Resource/Title coverage rather than the PCI coverage

To recreate:

• Add the "Taylor & Francis: Econ Konsortium Leibniz" package to an Agreement
• View the "E-resources covered by this agreement" section of the Agreement. Note that the coverage listed for "Accounting, business & financial history" is 1/1/1998, Vol:8 -> 12/31/2010, Vol:20
• Export as JSON
• See that in the exported file the coverage is

  "startDate": "1997-01-01",
  "endDate": "2011-12-31",
  "startVolume": "7",
  "startIssue": "1",
  "endVolume": "20",
  "endIssue": "3",

I believe this to be the TI or PTI coverage statement rather than the PCI coverage statement

Applies to JSON export