[Release] Java jars verification pass despite that nothing has been uploaded

Build do pass, despite that I forgot to upload the java binaries: https://github.com/ursacomputing/crossbow/runs/7587084181?check_suite_focus=true

cc @assignUser @raulcd

**Reporter**: [Krisztian Szucs](https://issues.apache.org/jira/browse/ARROW-17260) / @kszucs

_{**Note**: *This issue was originally created as [ARROW-17260](https://issues.apache.org/jira/browse/ARROW-17260). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start with the linked Crossbow workflow run (7587084181) and inspect the release verification step that passed without uploaded Java binaries. Trace how the Java jar presence is checked, then make the verification fail when those binaries are absent and confirm the behavior in the release workflow.

Written by the indexing model from the issue text.