Investigate how msgIdProvider are generated in Waku Relay

[fryorcraken]

This is a investigation request

Problem

See waku-org/nwaku#1556

Proposed Solutions

Understand what is done in js-waku and ensure it's aligned with go-waku and nwaku.

Notes

The behaviour is most likely inherited from @ChainSafe/libp2p-gossipsub and it's unclear whether we can override it.

[weboko]

msgId configuration is defined here and can be influenced by msgIdFn options passed to GossipSub class.

If not passed depending on Sign policy it will use one of pre-defined implementations. In our case for StrictNoSign it will be this one which is essentially sha256.

For nwaku we use sha256 as defined here and the same goes for go-waku

Hereby I declare implementations are on the same page. 📜

UPD: to prevent potential problem if ChainSafe stops using sha256 for StrictNoSign we can define option for PubSub on our side.