fix: silence GenAI audio optional dependency import warning

[sipercai]

Description

Fixes #217.

This removes the import-time warning from opentelemetry.util.genai._multimodal_upload.pre_uploader when optional audio conversion dependencies (numpy or soundfile) are not installed. The PCM16-to-WAV conversion path still logs a single warning when conversion is actually attempted and cannot be performed.

The change is intentionally scoped to loongsuite-otel-util-genai. loongsuite-site-bootstrap is out of scope because its stdout success line already has the LOONGSUITE_PYTHON_SITE_BOOTSTRAP_LOG_SUCCESS=False mitigation in the released package.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• python -m ruff check util/opentelemetry-util-genai/src/opentelemetry/util/genai/_multimodal_upload/pre_uploader.py util/opentelemetry-util-genai/tests/_multimodal_upload/test_pre_uploader_audio.py util/opentelemetry-util-genai/CHANGELOG.md
• PYTHONPATH=util/opentelemetry-util-genai/src:opentelemetry-instrumentation/src python -m pytest util/opentelemetry-util-genai/tests/_multimodal_upload/test_pre_uploader_audio.py -q
• PYTHONPATH=util/opentelemetry-util-genai/src:opentelemetry-instrumentation/src python -m pytest util/opentelemetry-util-genai/tests -q
• Temporary QwenPaw 1.1.12 + DashScope qwen3-max real API smoke comparing release util against this PR util overlay; release emitted the reported warning, PR overlay did not.
• Temporary QwenPaw instrumentation pytest run with QwenPaw 1.1.12 and this PR util overlay.
• tox -e precommit

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

Validation Evidence

Spec and Scope

• Linked issue/spec: numpy or soundfile not available, PCM16 to WAV conversion will be skipped #217
• Approved spec/comment: direct bug fix request; loongsuite-site-bootstrap explicitly excluded from this PR because the released 0.6.1 package already supports LOONGSUITE_PYTHON_SITE_BOOTSTRAP_LOG_SUCCESS=False.
• Changed surface: loongsuite-otel-util-genai multimodal pre-uploader optional audio dependency handling.

Local Checks

Check	Command	Result	Notes
Static readiness	python "$PIPELINE_SKILL_DIR/scripts/check_loongsuite_pr_readiness.py" --repo .	pass	Warned that no instrumentation plugin directory changed; expected for shared util-only change.
Precommit	tox -e precommit	pass	First run reformatted one test file; rerun passed.
Focused tests	PYTHONPATH=util/opentelemetry-util-genai/src:opentelemetry-instrumentation/src python -m pytest util/opentelemetry-util-genai/tests/_multimodal_upload/test_pre_uploader_audio.py -q	pass	16 passed.
Full util tests	PYTHONPATH=util/opentelemetry-util-genai/src:opentelemetry-instrumentation/src python -m pytest util/opentelemetry-util-genai/tests -q	pass	270 passed, 1 skipped (OSS credentials not set).
QwenPaw focused tests	LOONGSUITE_PYTHON_SITE_BOOTSTRAP=False PYTHONPATH=instrumentation-loongsuite/loongsuite-instrumentation-qwenpaw/src:util/opentelemetry-util-genai/src:opentelemetry-instrumentation/src python -m pytest instrumentation-loongsuite/loongsuite-instrumentation-qwenpaw/tests util/opentelemetry-util-genai/tests/_multimodal_upload/test_pre_uploader_audio.py -q	pass	29 passed in a temporary QwenPaw environment.
Claude review	claude_team_review.py review . --backend review ...	pass	One non-blocking suggestion about exact test assertion disputed; exact assertion is intentional to prevent duplicate warning regression.
Privacy scan	git diff | rg -n "sk-[A-Za-z0-9]|DASHSCOPE_API_KEY|OPENAI_API_KEY|ANTHROPIC_API_KEY|Bearer [A-Za-z0-9]|/Users/sipercai|/tmp/codex-claude-review|private trace|trace_id|traceId" || true	pass	No matches.

Real E2E Matrix

Scenario	Status	Command or Demo	Evidence
non-streaming	pass	Temporary QwenPaw 1.1.12 + DashScope qwen3-max AgentRunner.query_handler smoke with release util and PR util overlay.	Release util stderr started with numpy or soundfile not available...; PR util overlay removed that line. Both runs completed with real_api_chunks=5 last=True.
streaming	pass	Same QwenPaw async generator smoke.	The runner yielded streamed chunks and completed successfully with PR util overlay.
concurrency	N/A	Import-time warning side effect is process startup behavior; no shared mutable runtime path changed.	Covered by subprocess import regression with optional audio libs blocked.
agent/tool/ReAct	N/A	This PR does not change QwenPaw/AgentScope agent or tool instrumentation.	QwenPaw runner smoke was used only to validate the customer startup path.
tool-heavy	N/A	No tool execution behavior changed.	Not applicable to optional audio dependency import logging.
error path	pass	test_pcm16_conversion_missing_audio_libs_logs_single_warning	Missing audio libs during actual PCM16 conversion produce exactly one conversion-skip warning and keep original audio/pcm16 content type.

Telemetry and Weaver

Check	Status	Command or Artifact	Notes
Span tree / span kinds	N/A	N/A	No GenAI span creation, attributes, parent-child relationships, or exporter behavior changed.
Content capture modes	N/A	N/A	No content-capture semantics changed.
Concurrency isolation	N/A	N/A	No trace/context propagation or shared runtime telemetry state changed.
Weaver live-check	N/A	N/A	No telemetry sample shape changed; this PR only removes import-time optional dependency logging.

CI

• GitHub checks: not available until the branch is pushed and PR is opened.
• Known unrelated failures: none.
• Follow-up needed: inspect CI after PR creation.