mod-kb-ebsco-java can not work with the Eureka Keycloak clients due to the absence of the user_id field in x-okapi-token

The Eureka platform supports two authorization methods: ordinary users and Keycloak clients.

In the case of Keycloak clients, the folio-holdingsiq-client encountered a problem when the user_id was missing from the x-okapi-token. This resulted in a failure while trying to store the configuration in the cache because it requires the format user_id: Configuration_class_object, and the key cannot be null. Consequently, this leads to the following error during the request.

The error happens here

x-okapi-token example:

You should change that behavior to meet the Eureka platform needs.

1. Update: The issue appears on any environment at any time with the Keycloak client credentials token.
   
   To reproduce:
   1. Request the following endpoint to get the client credentials.
   https://<keycloak-url>/realms/<tenant_name>/protocol/openid-connect/token
   The body should contain the
   client_id: <SOME_CLIENT_ID>
   client_secret: <SOME_CLIENT_SECRET>
   grant_type: "client_credentials"

2. Request the following endpoint with the previously obtained credentials putting them in the header with the Authorization key.
   https://{{kong_fqdn}}/eholdings/kb-credentials/80898dee-449f-44dd-9c8e-37d5eb469b1d
   and with the following body

the content type should be the following application/vnd.api+json