Supervisor telemetry not flushed on error

[ranweiler]

Information

• Onefuzz version: 1.0
• OS: Any

Provide detailed reproduction steps (if any)

Create a job (or task) with a target setup script that exits nonzero.

Expected result

Error log telemetry appears in App Insights.

Actual result

It does not appear. This is because we early return in the error path, without flushing error telemetry.