Deprecate decoding msg! events to improve errorOnDecodeFailure event parsing.

[nicholasgodfreyclarke]

Anchor decodes events by checking if the transaction log line starts with "Program log:" (msg! system call) or "Program data" (sol_log_data system call).
This means that it attempts to decode all program logs.
After anchor 0.23.0 (2022-03-20) anchor switched to emitting events using the sol_log_data system_call (#1608).
This created a clear distinction between anchor events logs and logs for other purposes.

The problem being that when you pass errorOnDecodeFailure=true to parseLogs it will fail on all non anchor event program logs.
I propose deprecating attempting to parse msg! logs so anchor only attempts to parse genuine anchor event candidates.

[vercel]

@nicholasgodfreyclarke is attempting to deploy a commit to the coral-xyz Team on Vercel.

A member of the Team first needs to authorize it.

[Henry-E]

It looks like some of the tests are failing for this? I think maybe the tests are still expecting the old behaviour.

Out of interest, how much of a breaking change will this be for people that use it expecting the old behaviour?

Need to figure out those parts and then we can decide if it's ok to merge. Plus need to add a changelog if we do go ahead with the breaking change.