Investigate whether `client.ForceMetadataRefresh()` is necessary

[marclop]

When constructing the common Kafka client, a call to the ForceMetadataRefresh method is issued. It may not be necessary to do so, since the kgo.Client will issue a call to that method when it needs to.

apm-queue/kafka/common.go

Lines 294 to 295 in 8c6a813

	// Issue a metadata refresh request on construction, so the broker list is populated.
	client.ForceMetadataRefresh()

[simitt]

@marclop how expensive is this operation? Trying to get a sense of urgency for this.

[marclop]

It's not expensive, but it makes some unit tests flaky. I haven't yet seen this happen badly in the CI, so I think we can defer.