Add jh testcase format in metadata check job

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What does this MR do and why?

JH QA team noticed that the newly added qa:metadata-lint job in main-jh is failing. Job link.

After analyzing, we found:

1. The TESTCASE_FORMAT regex only supports the GitLab URL pattern: https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/\d+.
2. The JH test case URL follow the pattern: https://jihulab.com/gitlab-cn/quality/testcases/-/quality/test_cases/\d+.

Due to this, the qa:metadata-lint job fails as it cannot recognize the JH test case URL. Code:

TESTCASE_FORMAT = %r{https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/\d+}

    unless TESTCASE_FORMAT =~ test['testcase']
      testcase_format_errors.push(
        <<~FORMAT_ERRORS
           ==> #{test['testcase']} in file: #{test['id']} with title:
               #{test['full_description']}
        FORMAT_ERRORS
      )
    end

To resolve this issue, I have updated the TESTCASE_FORMAT to include the JH test case URL pattern:

TESTCASE_FORMAT = %r{
  (https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/\d+)|
  (https://jihulab.com/gitlab-cn/quality/testcases/-/quality/test_cases/\d+)
}x

So, I am creating this MR to append the JH test case URL pattern to the TESTCASE_FORMAT. This change will not affect the upstream code but will ensure that the qa:metadata-lint job can successfully parse the JH URLs and pass.

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