rpc can't server state based data until persisted
When the blocks are in memory and is not persisted to the database, during that time rpc requests raise an exception due to 
https://github.com/status-im/nimbus-eth1/blob/9b666860db290f9d249fc4df80581fe6375d78d6/nimbus/rpc/server_api.nim#L60-L66

One of the ways is to replay the state, but on every rpc request state getting replayed might be a bad idea.
This also directly affects the working of `eth_getTransactionCount` endpoint raising an exception and stopping the `blob-spammer` of kurtosis