SOLR-16678 Collection API v2 CREATE does not handle user-defined properties

[stillalex]

https://issues.apache.org/jira/browse/SOLR-16678

Description

SOLR-16678 is not a bug, it's using outdated syntax. Adding a test to showcase this, because I could not find an already exiting one.

Solution

Please provide a short description of the approach taken to implement your solution.

Tests

Please describe the tests you've developed or run to confirm this patch implements the feature or solves the problem.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide

[stillalex]

I don't see how the failures are related to this PR. I only introduced an extra test

[HoustonPutman]

They are likely unrelated. You can look here for tests that fail "often": http://fucit.org/solr-jenkins-reports/failure-report.html

[gerlowskija]

LGTM, thanks for the test Alex. Gonna aim to merge later today.

[gerlowskija]

(Tests pass for me locally - the Crave failures appear to be known flaky tests, so I'm going to proceed with merging.)