refactor: clean up min/max task count limits in streaming task autoscaler

[jtuglu1]

Description

This makes auto-scaling min/max handling done in a single place (since it is common logic shared by all auto-scalers) in the supervisor dynamic task call action. This also cleans up the task auto scaler contract of returning -1 only when the scaler failed to produce a desired task count (lack of metrics, etc.). Otherwise, it is expected to return a task count that the supervisor will then audit/clamp.

Release note

Clean up min/max task count limits in streaming task autoscaler

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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.