Prometheus/OpenMetrics output for timer is incorrectly scaled when non-default units specified in metadata

[tjquinno]

Environment Details

• Helidon Version: 2.4.2, 2.5.0
• Helidon SE or Helidon MP MP
• JDK version:
• OS:
• Docker version (if applicable):

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Problem Description

The values for a timer reported in Prometheus format are incorrect when the timer metadata specifies units of seconds. The reported are off by several powers of 10.

Steps to reproduce

1. Create a new MP QuickStart app. Add this to the GreetResource#getDefaultMessage method:

   @Timed(name = "gets", absolute = true, unit = MetricUnits.SECONDS)

2. Build and run.
3. curl http://localhost:8080/greet
4. curl -H "Accept: application/json" http://localhost:8080/metrics/application | jq
   Notice the very small values reported.
5. curl http://localhost:8080/metrics/application
   Notice the much larger values reported.