fix(tests): reset OTel tracer provider to None to stop cross-test recursion

[morgan-wowk]

Problem

Running the full tests/ suite produced 6 failures that were not reproducible when the affected files were run in isolation:

FAILED tests/test_container_execution_refresh_retries.py::...::test_missing_workload_is_counted_and_terminalizes
FAILED tests/test_container_execution_refresh_retries.py::...::test_retriable_errors_below_budget_leave_execution_running
FAILED tests/test_container_execution_refresh_retries.py::...::test_successful_refresh_resets_the_budget
FAILED tests/test_container_execution_refresh_retries.py::...::test_retry_moves_execution_to_the_back_of_the_queue
FAILED tests/test_container_execution_refresh_retries.py::...::test_failing_execution_does_not_hold_up_the_queue
FAILED tests/test_orchestrator_failed_log_upload.py::test_failed_execution_survives_log_upload_failure

The failures were a symptom (SYSTEM_ERROR instead of PENDING, mocks never called, timestamps not advancing), with a RecursionError: maximum recursion depth exceeded buried in the output.

Root cause

The reset_otel_providers autouse fixture in tests/instrumentation/opentelemetry/conftest.py reset the global tracer provider to a fresh ProxyTracerProvider():

trace._TRACER_PROVIDER = trace.ProxyTracerProvider()   # ← self-referential

OpenTelemetry's ProxyTracerProvider.get_tracer() delegates to the module-global trace._TRACER_PROVIDER. Once that global is a ProxyTracerProvider, the delegation points back at itself, so start_as_current_span recurses until RecursionError.

Because the fixture mutates OTel's process-global state, the broken provider leaked out of the opentelemetry/ test package into the rest of the suite (default collection order runs it before test_container_execution_refresh_retries). Later tests that emit spans via orchestrator_tracing.operation_span / execution_tracing.emit_execution_trace hit the RecursionError; the orchestrator caught it as a generic processing error and drove container executions to SYSTEM_ERROR, which is what the assertions actually tripped on.

Fix

Reset to None, matching the meter-provider reset on the very next line:

trace._TRACER_PROVIDER = None

With None, get_tracer_provider() falls back to OTel's internal _PROXY_TRACER_PROVIDER and ProxyTracer resolves to the no-op tracer — no self-delegation, no recursion.

Verification

• Before: 6 failed, 462 passed (full suite)
• After: 468 passed (full suite, pytest tests/)
• The previously-failing files still pass in isolation, and the opentelemetry/ suite that owns the fixture continues to pass.

Downstream

This is beneficial to downstream applications with their own suite of tests against OTEL.