allow detecting calls to contracts through event data

[MicaiahReid]

Currently, the contract_call predicate can check if a contract call is made to a specific method of that contract. It does this by checking the transaction and not the events that are generated from that transaction.

If a user wants to detect any contract calls that are made via another contract, that currently isn't possible. We should expand the contract_call predicate, or make a new predicate, which allows matching sub contract calls. See this discussion on discord for some possible matching patterns.