Knowledge base articles not visible for "Customers"

Service Desk customers are able to access KB articles

Service Desk knowledge base help
Integrating with Confluence

Original bug description

With the agent based pricing for Service Desk, we have now 3 different user types on JIRA end:
Customers
Users
Agents

Customers have user credentials on the JIRA instance, which poses an issue when this JIRA instance is connected to a Confluence instance, and uses the knowledge base functionality.

When using an Impersonating authentication type application link, the Customer will not be able to access the knowledge base articles, since their user does not have application access to Confluence. Allowing anonymous access to the space of the knowledge base does not take priority over a blocked user authentication based on application access.

When using an Non-impersonating authentication type application link, this will have implications for JIRA Users who also use Confluence, but beyond the spaces used for the Knowledge Bases.

This prevents proper knowledge base access configuration to Customers with the new agent based pricing model.