Fix TxWitness text envelope formatting for the Shelley era

Fix 4493 bug - essentially the type field in the Shelley era text envelope tx body was being written to disk as "TxWitnessShelley" and being read from disk as "TxWitness Shelley". I.e there was a mismatch and therefore it was not possible to read shelley era transaction bodies.

Closes: IntersectMBO/cardano-node#4493

src/Cardano/CLI/Shelley/Run/Transaction.hs

@@ -1759,7 +1759,7 @@ acceptKeyWitnessCDDLSerialisation err =
     firstExceptT (ShelleyTxCmdTextEnvCddlError tEnvErr)
           $ newExceptT $ readFileTextEnvelopeCddlAnyOf teTypes fp
 
-  teTypes = [ FromCDDLWitness "TxWitness Shelley" CddlWitness
+  teTypes = [ FromCDDLWitness "TxWitness ShelleyEra" CddlWitness
             , FromCDDLWitness "TxWitness AllegraEra" CddlWitness
             , FromCDDLWitness "TxWitness MaryEra" CddlWitness
             , FromCDDLWitness "TxWitness AlonzoEra" CddlWitness