store sync should fetch block of latest block number alongside logs

[holic]

see #2315 (comment)

load balanced RPCs may be slightly out of sync, so when we get a notif for latest block number from a subscription, then fetch logs for that block number, the underlying rpc may not yet have the logs and return empty array

ideally we should fetch the block alongside the logs for that block to confirm the rpc has it, otherwise retry

(and need to handle/account for rpcs that don't support batch calling in this way)