fix(deps): expand OpenTelemetry upper bound to 1.43.0

Expand the opentelemetry-api and opentelemetry-sdk upper bound from
<=1.42.1 to <=1.43.0 so downstream projects (e.g. ZenML 0.96.2 which
requires opentelemetry-sdk==1.43.0) can resolve dependencies without
conflicts.

The expansion is narrow (one release) and preserves the existing lower
bound. ADK's full telemetry test suite passes with 1.43.0 — verified
locally: 275 passed, 2 pre-existing Windows-only failures unrelated to
this change (resource module / instrumentation platform check).

Fixes #6421

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

Author: Varshith-Kali

pyproject.toml

@@ -40,8 +40,8 @@ dependencies = [
   "graphviz>=0.20.2,<1",
   "httpx>=0.27,<1",
   "jsonschema>=4.23,<5",
-  "opentelemetry-api>=1.39,<=1.42.1",
-  "opentelemetry-sdk>=1.39,<=1.42.1",
+  "opentelemetry-api>=1.39,<=1.43.0",
+  "opentelemetry-sdk>=1.39,<=1.43.0",
   "packaging>=21",
   "pydantic>=2.12,<3",
   "python-dotenv>=1,<2",