Header for X-Openid-Configuration should consider only necessary attributes to decrease the size for header values

Current Situation

When logging in with an OIDC Identity Service, the login endpoint is forwarded the X-Openid-Configuration header which holds the answer of the .well-known/openid-configuration endpoint. The header value is base64 encoded.

The header is sent to avoid a second call to the .well-known/openid-configuration executed by the JOC Cockpit REST Web Service API.

The value can exceed the 8 KB limit for individual header values imposed by some browser products. The overall limit for all headers is asssumed to be 256 KB.

Desired Behavior

The X-Openid-Configuration header should contain base64 encoded attributes from the answer of the .well-known/openid-configuration endpoint only as required by the login endpoint. Required attributes include "claims_supported" and "jwks_uri".

If the size of the X-Openid-Configuration header is greater than 8KB, the header can be be omitted. In this case, the JOC Cockpit REST Web Service API would call the .well-known/openid-configuration endpoint again.