Remove logging of collector payloads

[istreeter]

There are three places in the code base where we potentially log event-level data: here in beam enrich, here in stream enrich and here in enrich-pubsub. That last one is a debug level, which is probably OK.

From a data governance point of view, logs are much more difficult to manage if they potentially contain customer data.

[istreeter]

This issue was spotted during an investigation of CVE-2021-44228. But to be clear, this is not supposed to be our primary safeguard against that CVE. Rather, it's just something we should do anyway.

More details about CVE-2021-44228 impact on Snowplow apps on Discourse