DecodeAccountKey for new AddAccountKey event format

[bthaile]

Instructions

Problem

flow.AccountKeyAdded has two formats from GetEventsForHeightRange, I've been told that the events are from on-chain and can not be reformatted from server. There is a helper flow.DecodeAccountKey(pkBytes) for process the old format. I don't see any helpers for processing the new format.

new format example in json

https://gist.github.com/bthaile/8e2c600797da0d47d7766b5079c69962

old format example in json

https://gist.github.com/bthaile/1244c7a4d6fbf755dbab2caf898ee742

Steps to Reproduce

query := client.EventRangeQuery{
Type: "flow.AccountKeyAdded",
StartHeight: lowHeight,
EndHeight: highHeight,
}

set the block range for the past 100 blocks and keep pulling every 100 blocks and eventually you will see the new format. Most of the event's I'm seeing are in the old format

events, err := client.GetEventsForHeightRange(context, query)

Acceptance Criteria

Helper method to parse new AccountKeyAdded event publicKey 64 byte array.
old AccountKeyAdded event format has publicKey as a 73 bytes array

Context

Building public key indexer that maps public keys to account addresses. I can reduce calls to Access Node by using event data.

[turbolent]

@bthaile Coud you please add the code for the decoding function you have so far (what we discussed on Slack)?