Babbage blocks fail decoding to CBOR

Log:

```
Failed to unmarshal CBOR data into BabbageBlock: cbor: cannot unmarshal array into Go struct field babbage.tBabbageBlock.BlockHeader of type babbage.BabbageBlockHeaderBody (cannot decode CBOR array to struct with different number of elements)
```

This is happening in #1091 and is also preventing creating a similar test for UTxORPC.