Event filter in `market.ts` must verify the event emitter address

[jkrivine]

Describe the bug
The following loop is just checking the event name, so a contract different from Mangrove could emit it and potentially confuse the API.

for (const evt of receipt.events) {
      if (evt.event === "OrderComplete") {
        if ((evt as OrderCompleteEvent).args.taker === receipt.from) {
          result = evt;
        }
      }
    }