According to https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata:

The server MUST support the openid scope value. Servers MAY choose not to advertise some supported scope values even when this parameter is used, although those defined in OpenID.Core SHOULD be listed, if supported.

Keycloak need to be extended in order to be able to hide client scopes from discovery( OpenID Provider Metadata).

We make this PR in order to implement it. Details can be found in github issue.
Could you review it?