Proposal for GenAI Security fields

[susan-shu-c]

Related to: https://github.com/open-telemetry/semantic-conventions/issues/1034

Changes

Proposing the following fields that enable security detections to protect LLMs from attacks, misuse (violations, compliance etc.). For example these detection rules.

gen_ai.policy.name	
gen_ai.policy.action
gen_ai.policy.confidence
gen_ai.compliance.violation_detected
gen_ai.compliance.violation_code
gen_ai.performance.request_size

Merge requirement checklist

• [ ] CONTRIBUTING.md guidelines followed.
• [ ] Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• [ ] schema-next.yaml updated with changes to existing conventions.