Auto-requires are generated on

(java-headless or java-17-headless or java-11-headless or java-1.8.0-headless)

but since OpenJDK 21 is in RHEL 9, auto-requires should be:

(java-headless or java-21-headless or java-17-headless or java-11-headless or java-1.8.0-headless)

or dropped entirely.

Update javapackages-config.json to include java-21-headless in the auto-requires string, or not to generate Java auto-requires at all.

Testing:
Tests for javapackages-tools are maintained in tmt format at https://src.fedoraproject.org/tests/javapackages-tools
The test suite includes tests for building packages and asserting their Requires: /Sanity/build-maven and /Sanity/build-package
The tests need to be adjusted to check for appropriate Requires in built packages.

Acceptance criteria:

• javapackages-config.json is updated to include java-21-headless, or not to generate Java auto-requires at all
• /Sanity/build-maven and /Sanity/build-package are updated and pass

This change is intended to be delivered in RHEL 9.6 Y, 9.5 0day and 9.4 Z.
The original Jira issue is for Y-stream RHEL 9.6, please clone it and adjust for Z-stream as appropriate.