`RemoveRolesFromCompositeAsync` uses strange serialisation and fails

[AShtifanovBK]

hi, i have noticed, that this method is using some strange serialisation that is nowhere used in the project:

https://github.com/lvermeulen/Keycloak.Net/blob/5870da22392273b1a6171769115ec7061a4b809a/src/Keycloak.Net/RolesById/KeycloakClient.cs#L54

and this method fails due to this, i suppose.

Good that there is another method RemoveCompositesFromRoleAsync which still works: https://github.com/lvermeulen/Keycloak.Net/blob/5870da22392273b1a6171769115ec7061a4b809a/src/Keycloak.Net/Roles/KeycloakClient.cs#L81