Fixing http entity test case

[cryptoe]

Description

Fixes the unit test HttpEntity which was contacting https://druid.apache.org/data/wikipedia.json.gz. Changed it in a way that a local server gets started in the unit test and shuts down when the UT is finished.

The uber goal was to fix #10853 but that is tricky as it would require a new Nginx docker image to be bundled to serve static contents.
Will defer it until #12368 makes it into master.

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Key changed/added classes in this PR

• HttpEntityTest

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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.
• 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.

[kfaraz]

@cryptoe , I agree that it is weird to contact the ASF served druid.apache.org/wikipedia but I am not entirely sure if starting a local server in a unit test is the right solution for this.

Would it be possible to do this through a mock or through a file uri rather than an http endpoint?

[cryptoe]

Raised a different PR : #12671

[cryptoe]

@cryptoe , I agree that it is weird to contact the ASF served druid.apache.org/wikipedia but I am not entirely sure if starting a local server in a unit test is the right solution for this.

Would it be possible to do this through a mock or through a file uri rather than an http endpoint?

In this case, mocking does not actually test anything hence went ahead with the file based approach.
Thanks for the review @kfaraz