[opentelemetry-instrumentation-google-genai] Add response ID attribute to the interactions API telemetry (inference span and event)

[DylanRussell]

Description

Set response id attribute to interactions.id

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How has this been tested?

Unit tests

Checklist

See CONTRIBUTING.md
for the style guide, changelog guidance, and more.

• Followed the style guidelines of this project
• Changelog updated if the change requires an entry
• Unit tests added
• Documentation updated

[Copilot]

Pull request overview

Adds support for the GenAI semantic convention gen_ai.conversation.id in the shared opentelemetry-util-genai inference invocation, and wires it into the opentelemetry-instrumentation-google-genai Interactions API by mapping previous_interaction_id to that attribute.

Changes:

• Add conversation_id to InferenceInvocation and include it in span + inference-operation-details event attributes.
• Populate invocation.conversation_id for interactions.create (sync + async) from previous_interaction_id / config.
• Add unit tests and changelog fragments for both the util and google-genai instrumentation packages.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
util/opentelemetry-util-genai/tests/test_utils.py	Adds a unit test for InferenceInvocation.conversation_id on spans (suggested to also assert the emitted event).
util/opentelemetry-util-genai/src/opentelemetry/util/genai/_inference_invocation.py	Adds conversation_id field and emits gen_ai.conversation.id via _get_attributes() (affecting span + event).
util/opentelemetry-util-genai/.changelog/233.added	Changelog entry for util-genai conversation_id support.
instrumentation/opentelemetry-instrumentation-google-genai/tests/interactions/base.py	Adds a test asserting gen_ai.conversation.id is set from previous_interaction_id (suggested to also assert the event).
instrumentation/opentelemetry-instrumentation-google-genai/src/opentelemetry/instrumentation/google_genai/interactions.py	Sets invocation.conversation_id from previous_interaction_id for sync/async interactions.create.
instrumentation/opentelemetry-instrumentation-google-genai/.changelog/233.added	Changelog entry for google-genai interactions telemetry including conversation.id.

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