Restore private channel support

[mwarkentin]

It'd be great if we're able to gib potatoes in pribate channels again (in a way that we're happy with security-wise).

I find myself gibing potatoes that don't work, or not gibbing a potato at all because I have to find a different channel to do it in.

[mwarkentin]

All go transactions to the event endpoint had the message in their payload. We can remove them in the SDK. (Also, server side scrubbing was turned off as well).

Summarizing:

• Messages which included 🥔 in private channels were sending the message text to gibpotato
• All messages from private channels with gibpotato installed were being sent and filtered by the gibpotato golang service
• gibpotato was not storing the messages itself, but our tracing was sending this data to sentry
• We should scrub this data in the SDK
• We should also look at configuring server-side scrubbing for this data

If we do this, could that be enough to re-enable gibpotato on our private channels?