MTG 1289 Fix redis_total_accounts_parsed metric

[n00m4d]

What

This PR fixes counting redis_total_accounts_parsed metric. The issue is that value is incremented by result.len() but if self.message_parser.parse_account(item.data, false) returns empty vector we don't write anything to the result vec, but message was processed by fact. Parse_account method may return empty vector if it received account with program owner which we don't support. So as a result of this issue we can see not very informative metric on Grafana - Unparsed Transactions & Accounts, which looks like ingester cannot parse all the data, but it's wrong, we see it only because values in metric were not calculated correctly. It didn't happen before because previous Solana snapshot ETL was using Geyser plugin which has accounts filter inside and it sent only accounts which Aura supports. But with PR metaplex-foundation/digital-asset-validator-plugin#88 now ETL sends all the accounts from the snapshot.

[armyhaylenko]

LBTM, i generally agree
the metric i did originally would probably better called redis_total_accounts_written and not processed.