Fix: Guarantee health::status KVP emission via function-level span

[peytonr18]

Despite my earlier PR to enable pre-HTTP telemetry emission, _report still fails to emit to .kvp because it closes immediately after the Wireserver connection is established and the root span exits. By creating a custom span for the _report function, it ensures that health::status events are included, regardless of the main span exiting.

Solution

• Ensure the kvp_writer has an active span for _report to use outside of the PROVISIONING_REPORT.
  • Achieved by adding a function-level span on _report called health_status.
• Added message "Provisioning report: {}" to the health_report event in _report() for visibility in azure-init.log