In WSO2 Integration Cloud, we provide WSO2 ESB as an app type. So you can configure to FHIR connector on WSO2 ESB.
At the moment we don't have a specific document on configuring the FHIR connector on WSO2 Integration Cloud. But, we have included an example document  on how to configure a sample (Twitter) connector. This is a general guide a user can follow, it shows how to create a CAR file and import it onto the Integration Cloud.
For information on configuring the FHIR connector, you can follow the document here.
Please note that if you wants to add custom server certificates into the client truststore or requires any custom configurations, you need to create custom docker image and deploy it in WSO2 Integration Cloud. 
IntegrationCloud/Use+a+WSO2+ ESB+Connector+to+Invoke+Third+ Party+Functionality