Remove restriction on possible hosts for Java tracer URL

[nikita-tkachenko-datadog]

Requirements for Contributing to this repository

• Fill out the template below. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• The pull request must only fix one issue at the time.
• The pull request must update the test suite to demonstrate the changed functionality.
• After you create the pull request, all status checks must be pass before a maintainer reviews your contribution. For more details, please see CONTRIBUTING.

What does this PR do?

When using auto-configuration for Test Visibility for Java, it is possible to use DATADOG_JENKINS_PLUGIN_TRACER_DISTRIBUTION_URL environment variable for specifying custom URL that is used for downloading the Java tracer.
Currently it is only possible to specify URLs that point to Maven Central.
There is a customer that wants to use their local artifactory instance for downloading the tracer artifact.
So this PR removes the URL host restriction to allow providing URLs to on-premises artifactory.

Description of the Change

Alternate Designs

Possible Drawbacks

Verification Process

Additional Notes

Release Notes

Review checklist (to be filled by reviewers)

• Feature or bug fix MUST have appropriate tests (unit, integration, etc...)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have one changelog/ label attached. If applicable it should have the backward-incompatible label attached.
• PR should not have do-not-merge/ label attached.
• If Applicable, issue must have kind/ and severity/ labels attached at least.

[drodriguezhdez]

LGTM