chore(deps): bump checkstyle to 13.9.0

[joaodinissf]

Summary

• bump Checkstyle from 13.8.0 to 13.9.0
• replace the removed JavadocStyle check with SummaryJavadoc
• add summary sentences required by the replacement check
• update the matching test-source suppression

This supersedes #1479, which only applies the dependency bump and therefore fails because Checkstyle 13.9.0 removed JavadocStyle.

Verification

• mvn -T 3C checkstyle:checkstyle checkstyle:check -f ./ddk-parent/pom.xml --batch-mode --fail-at-end
• mvn -T 3C clean verify -f ./ddk-parent/pom.xml --batch-mode --fail-at-end