[Backport] Skip generating task context reports for sub tasks (#17219)

[arunramani]

Description

TaskContextReports generated by subtasks are not utilized by the parent task or preserved in any way. This change removes the inclusion of the task context for child tasks. This also fixes an issue with rolling upgrades from the version before TaskContextReport existed to after.

Fixed the bug ...

Renamed the class ...

Added a forbidden-apis entry ...

Release note

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Key changed/added classes in this PR

• MyFoo
• OurBar
• TheirBaz

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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.

[ac9817]

clean cherry-pick #17219

[kfaraz]

Thanks for the backport, @arunramani !