4.x ServerCdiExtension creates metrics observers using its provider, even though the metrics extension already added it to the server

[tjquinno]

Environment Details

• Helidon Version: 4.0.0
• Helidon SE or Helidon MP MP
• JDK version:
• OS:
• Docker version (if applicable):

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Problem Description

With metrics the CDI extension creates the metrics observer using special settings beyond what might be in the normal place in configuration and then adds it to the server.

But even so, the ServerCdiExtension triggers creation of another metrics observer (because the metrics observer provider is on the class path) even though the metrics CDI extension already created one.

This duplication causes the global meter registry to be overwritten, discarding previously-registered meters and proceeding with incorrect configuration settings for the meter registry.

Steps to reproduce

cd microprofile/metrics
mvn test -Dtest=BadGaugeTest -Dmaven.surefire.debug # or any test that starts the server

Set a breakpoint at the MetricsObserver constructor.
It will be invoked twice, first from the MetricsCdiExtension and then from ServerCdiExtension gathering all observers via their providers.