Replace Data/U8a with un-aliassed Raw (#1656)

* Replace Data with un-aliassed U8a

* Export U8a

* Explicitly add U8a to the registry

* U8a -> Raw

packages/api-contract/src/base/Contract.ts

@@ -75,7 +75,7 @@ export default class Contract<ApiType extends ApiTypes> extends BaseWithTxAndRpc
 
       output = message.returnType
         ? formatData(this.registry, data, message.returnType)
-        : createType(this.registry, 'Data', data);
+        : createType(this.registry, 'Raw', data);
     }
 
     return {