KAFKA-8119; Ensure KafkaConfig listener accessors work during update

[rajinisivaram]

Use the same config to obtain all properties used in each KafkaConfig accessor method to ensure that validation doesn't fail if config was updated during the method.

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[ijuma]

Thanks for the PR. This seems a little error prone. Can we use the type system to make it less so?

[ijuma]

@rajinisivaram is this still relevant?

[rajinisivaram]

I think this is probably still relevant in the case of DynamicBrokerReconfigurationTest. But that could probably be fixed in the test itself. Will take a look at test failures to see if we are running into the issue.