Add metrics for number of rows/bytes materialized while running subqueries

[LakshSingla]

Description

This PR adds the metrics to analyze the size of the results materialized by the subquery's results on the heap. The following metrics are added:

subquery/rows - Number of rows produced by the subquery
subquery/bytes - Bytes produced by the subquery

Both the metrics have id and subQueryId in the dimensions.

Release note

subquery/rows and subquery/bytes metrics have been added, which indicate the size of the results materialized on the heap.

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Key changed/added classes in this PR

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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.

[cryptoe]

Could you please java doc why this dryRun flag is needed