feat: add helpers for deriving the claimant from an EventAction

[Quazia]

Description

We want to be able to get the claimant easily off of an EventAction given a txHash.

Suggested Solution

Function should be part of the EventAction.ts helpers and work very similarly to the current isActionStepValid function and the signature is probably something like:

public async getClaimantAddressFromTx(
  txParams: GetTransactionParameters,
): Promise<Address | undefined>