MSQ ingestion: Improve error message on encountering non-long timestamp column

[Akshat-Jain]

Description

This PR improves the error message during MSQ ingestion if we encounter a non-long timestamp column.

Sample error message shown to user:

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This PR has:

• been self-reviewed.
• 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.

[LakshSingla]

@Akshat-Jain can you add a test case for this? I doubt there is already one since you'd have to change the error message.

[Akshat-Jain]

@LakshSingla Have added tests for the method.