New error message for task deletion

[georgew5656]

Description

The fabric8 API returns false only if the K8s API returns a 404 on a delete attempt (resource not found). If there is a actual error than fabric8 will rethrow the client exception. Updating the log message to account for this.

See:
https://javadoc.io/static/io.fabric8/kubernetes-client/4.6.4/io/fabric8/kubernetes/client/dsl/base/BaseOperation.html#delete--

Key changed/added classes in this PR

Update DruidKubernetesPeonClient to handle false results from job.delete() differently.
This PR has:

• been self-reviewed.
  • using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.