[Bug] broken pruned tx hash 
The explorer shows seemingly random tx_hashes when `--prune-blockchain` is on [more info](https://github.com/moneroexamples/onion-monero-blockchain-explorer/issues/303) (note that it only happens with v2 txes above block height 1220517)

My guess it that something around `get_pruned_transaction_hash()` may be broken.