[Docs]:  Set final Fireball product version to 2.13.5 in common attributes file

UPDATE: The product build will be based on upstream version 2.13.5
This is because fixes from previous releases that failed acceptance tests needed to be applied upstream and the updated upstream artifacts needed to be re-built for productization.

The 2.13.5 build passed acceptance tests and has been promoted to candidate release.

Update the docs common content attributes.adoc file with the final product version 2.13.4.