fix(deps): expand OpenTelemetry upper bound to <=1.43.0

[Varshith-Kali]

Description

Fixes #6421

google-adk 2.3.0–2.5.0 constrain opentelemetry-api and opentelemetry-sdk to <=1.42.1. This prevents interoperability with projects that require opentelemetry-sdk==1.43.0 (e.g. ZenML 0.96.2 for FastAPI 0.138 support), leaving no overlapping version for dependency resolution.

This PR expands the upper bound from <=1.42.1 to <=1.43.0 — a narrow one-release bump that preserves the existing lower bound (>=1.39).

Changes

• pyproject.toml: opentelemetry-api and opentelemetry-sdk upper bound changed from <=1.42.1 to <=1.43.0

Why

The issue reporter (@dacongming0425) already validated that ADK 2.5.0 telemetry tests pass with OpenTelemetry 1.43.0:

• ests/unittests/telemetry/test_functional.py — pass
• ests/unittests/telemetry/test_spans.py — pass
• ests/unittests/telemetry/test_telemetry_context.py — pass

A narrow <=1.43.0 expansion is preferable to removing the upper bound entirely because ADK uses unstable OpenTelemetry log APIs that may break across releases.

Testing

Ran the full telemetry test suite locally with opentelemetry-api==1.43.0 and opentelemetry-sdk==1.43.0 installed:

275 passed, 2 failed, 18 warnings in 34.82s

The 2 failures are pre-existing Windows platform issues unrelated to this change:

1. est_detect_error_bash_tool — import resource is Unix-only
2. est_instrumented_with_opentelemetry_instrumentation_google_genai — platform-specific instrumentation check

Both failures reproduce on the unmodified main branch on Windows.

Testing Plan

• Telemetry unit tests pass with OTel 1.43.0
• CI multi-version test matrix (tox) passes on Linux

AI Assistance Disclosure

Drafted with AI assistance, reviewed and tested by me before submission.

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