4.x `MeterRegistry#meters()` can throw `IllegalStateException`

[tjquinno]

Environment Details

• Helidon Version: 4.x
• Helidon SE or Helidon MP SE
• JDK version:
• OS:
• Docker version (if applicable):

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Problem Description

Occasionally, a user is seeing code that has invoked MeterRegistry#meters() throw an exception like the one below.

Presumably, this is because a meter has been registered by another thread while the meters() method is running.

Helidon should protect against this.

java.lang.IllegalStateException: Accept exceeded fixed size of 104
	at java.base/java.util.stream.Nodes$FixedNodeBuilder.accept(Nodes.java:1233)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1787)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:575)
	at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(AbstractPipeline.java:260)
	at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:616)
	at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:622)
	at java.base/java.util.stream.ReferencePipeline.toList(ReferencePipeline.java:627)
	at io.helidon.metrics.providers.micrometer.MMeterRegistry.meters(MMeterRegistry.java:232)

Steps to reproduce