Not clear logged exception when listener.brokerCertChainAndKey has empty secret name

[ppatierno]

When, by mistake, a Kafka custom resource has a listener configuration with all empty fields for brokerCertChainAndKey, the cluster operator prints the following error which is not so clear to what it's referring to.

java.lang.IllegalArgumentException: Name must be provided.
	at io.fabric8.kubernetes.client.dsl.base.BaseOperation.withName(BaseOperation.java:255) ~[io.fabric8.kubernetes-client-4.12.0.jar:?]
	at io.fabric8.kubernetes.client.dsl.base.BaseOperation.withName(BaseOperation.java:84) ~[io.fabric8.kubernetes-client-4.12.0.jar:?]
	at io.strimzi.operator.common.operator.resource.AbstractResourceOperator.get(AbstractResourceOperator.java:210) ~[io.strimzi.operator-common-0.20.0.jar:0.20.0]
	at io.strimzi.operator.common.operator.resource.AbstractResourceOperator.lambda$getAsync$1(AbstractResourceOperator.java:223) ~[io.strimzi.operator-common-0.20.0.jar:0.20.0]
	at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$2(ContextImpl.java:313) ~[io.vertx.vertx-core-3.9.1.jar:3.9.1]
	at io.vertx.core.impl.TaskQueue.run(TaskQueue.java:76) ~[io.vertx.vertx-core-3.9.1.jar:3.9.1]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[?:?]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [io.netty.netty-common-4.1.50.Final.jar:4.1.50.Final]
	at java.lang.Thread.run(Thread.java:834) [?:?]

An example of such a custom resource is the following:

listeners:
    - name: plain
      port: 9092
      tls: false
      type: internal
    - name: tls
      port: 9093
      tls: true
      type: internal
    - configuration:
        bootstrap:
          host: <some-host>
        brokerCertChainAndKey:
          certificate: ""
          key: ""
          secretName: ""
        brokers:
        - broker: 0
          host: <some-host>
        - broker: 1
          host: <some-host>
        - broker: 2
          host: <some-host>
      name: external
      port: 9094
      tls: true
      type: route

Maybe it's referring to the secretName more specifically, but the error should clarify it.