build: attach javadoc jar to release builds

[marevol]

Summary

Release builds did not generate javadoc jars because maven-javadoc-plugin in the root pluginManagement had no jar goal execution, while the core and toolkit modules only declare the plugin without executions. The super POM release-profile that used to handle this is no longer available in current Maven versions, so publishing to Maven Central fails validation during mvn release:perform. Sources jars were already covered by the existing maven-source-plugin execution.

Changes Made

• Add an attach-javadocs execution (jar goal) to maven-javadoc-plugin in the root pluginManagement, which the core and toolkit modules inherit

Testing

• Ran mvn package -DskipTests -pl core and confirmed that java-saml-core-*-javadoc.jar is generated alongside the sources jar

Additional Notes

• Same fix as build: attach sources and javadoc jars to release builds opensearch-runner#20 (codelibs/opensearch-runner@25c54af)