Remove unused commons-codec dependency management

[Caideyipi]

Summary

• remove the unused commons-codec version property
• remove the unused commons-codec dependencyManagement entry

Notes

• The source tree no longer references commons-codec directly after the existing external commons migration.
• commons-codec is still present as a transitive dependency in the current build, so the dependency reference list is intentionally unchanged.
• I checked downstream dependency-cleanup candidates. This is the only generally applicable leftover for upstream master; the other removals are either already covered by existing master changes or tied to downstream feature/module removal.

Testing

• git diff --check
• python -m json.tool dependencies.json
• mvn -nsu dependency:tree -Dincludes=commons-codec:commons-codec -DskipTests -DskipITs