Function is_chain_known 

pub async fn is_chain_known(
    id: &CatalystId,
    is_persistent: bool,
    context: &mut RbacBlockIndexingContext,
) -> Result<bool>

Returns true if a chain with the given Catalyst ID already exists.

This function behaves in the same way as latest_rbac_chain(...).is_some() but the implementation is more optimized because we don’t need to build the whole chain.