[Hybrid Agent] OTel Application Logging Improvements

Related to https://new-relic.atlassian.net/browse/NR-575934

The goal of this story is to improve the experience of using the OTel Logs API with the Java hybrid agent. Desired improvements include:

1. Stop rejecting logs without a message body
2. At least for OTel events, but perhaps in general, stop prefixing context. on attributes that we add to log messages
3. Put together a DACI on how to support OTel events
4. Put together a DACI on how to support OTel events that by convention get transformed to custom events (for example, should they be transformed in the agent and count towards the custom event reservoir?)
5. Convert errors/exceptions passed via logs into error events in our agents (I believe the Java/Node agents are already doing this today, but other agents are not)

Items 1, 2, and 5 are not necessarily hybrid agent specific, but they may improve the experience in a consistent manner across all logging frameworks and make things better for the hybrid agent experience. If this work does expand beyond the OTel Logs API then additional stories should be created to reflect the increased scope and keep it separate from the Hybrid Agent initiative.

This work will need coordination with the Logging teams and @alanwest . Relevant conversation related to internal testing opportunity: https://newrelic.slack.com/archives/C07PUH00WBZ/p1781125345332209