feat(ci_visibility): send error logs to telemetry endpoint

[gnufede]

Summary

• Adds record_error_log method to TelemetryAPI, delegating to the ddtrace telemetry writer's add_error_log
• Instruments 16 API client error paths and git-missing detection to submit internal errors to the telemetry logs intake
• Uses constant message strings (per check_constant_log_message.py guardrail) with exc_info for dynamic stack traces

Test plan

• Unit test for record_error_log basic call
• Unit test with exc_info tuple
• Unit test for NoOp writer (no add_error_log attribute)
• Verify error logs appear in Datadog Error Tracking via telemetry intake

Motivation

Per CI Visibility telemetry RFC: internal library errors should be uploaded to the telemetry logs endpoint for visibility in the Logs product and Error Tracking, matching .NET and Node.js tracer behavior.

🤖 Generated with Claude Code

[cit-pr-commenter-54b7da]

Codeowners resolved as

ddtrace/testing/internal/api_client.py                                  @DataDog/ci-app-libraries
ddtrace/testing/internal/session_manager.py                             @DataDog/ci-app-libraries
ddtrace/testing/internal/telemetry.py                                   @DataDog/ci-app-libraries
scripts/check_constant_log_message.py                                   @DataDog/apm-core-python
tests/testing/internal/test_telemetry.py                                @DataDog/ci-app-libraries