Re-export op-cert AsType constructors via Experimental.Certificate

Add `AsOperationalCertificate` and `AsOperationalCertificateIssueCounter`
to the `AsType` re-export list of `Cardano.Api.Experimental.Certificate`
so consumers that drop the public `Cardano.Api.Certificate` import have
a single place to pick up the op-cert data-family constructors.

Author: Jimbo4350

cardano-api/src/Cardano/Api/Experimental/Certificate.hs

@@ -35,7 +35,7 @@ module Cardano.Api.Experimental.Certificate
   , fromShelleyPoolParams
 
     -- * Data family instances
-  , AsType (AsCertificate)
+  , AsType (AsCertificate, AsOperationalCertificate, AsOperationalCertificateIssueCounter)
 
     -- * DRep and Stake Pool Ids
   , Hash (..)