Uncaught exception in bitcoin_rpc_client::getblock

We have an uncaught exception that leads to abort when we parse json, that comes from bitcoin_rpc_client::getblock.

Place in code:

https://gitlab.com/PBSA/peerplays/-/blob/develop/libraries/plugins/peerplays_sidechain/sidechain_net_handler_bitcoin.cpp#L450

Environment:

I use peerplays-qa-environment (bitcoin node version 0.21)

witness_node is latest from develop branch (last commit): 0e5d599f

Steps to reproduce:

1. Run fresh container for peerplays-qa-environment_bitcoin-for-peerplays_1
2. Run witness_node with config file from peerplays-all-in-one container
3. Execute ./init-network.sh from bitcoin container