fix json output for digest from RPC calls

[edwardmack]

Results from RPC calls that contain header responses, the digest results are not formatted as a hex string, instead results are shown as raw bytes.

Expected Behavior

 "digest": {
            "logs": [
                "0x066175726120b33bc10f00000000",
                "0x05617572610101180b4de13f74e206324c2b168b72acec4ceb563d3788a51e9671170cd23d426a7d6c444e7e3aed5ad65ae9a07ce9d14317601dcce7a2660638ddfccc460a6882"
            ]
        },

Current Behavior

 "digest": [
            "AUJBQkUqwA/Tab4jGXRT1DnPUe+OPAzd1XbAYggcfYJpd9LGcrWY+ixNWMq6aoICoTqxBau2Cz4RZpLkSIsmnbAAtJEPtNDynEtllnhb+vfnMlbdSWDXEo/Ipb9tUWJHiuEH6g8AAAAAAAAAAG4HAAAAAAAA",
            "BEJBQkVaX75EtA7tF/9Vz2bcVHRjc0EHLnOSFrIPP+7VGc8We2GbQoYqkp7as+1PLyvnM3+Mh4gt+h1hbZEz2Kq3U7OH"
        ]

Possible Solution

Steps to Reproduce (for bugs)

1. RPC call chain_getHeader or chain_getBlock

Context

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