Update Hilla/Lit docs for Production Builds to use vaadin-maven-plugin

[rbrki07]

The Hilla docs for Production Build (articles/hilla/guides/production/production-build.adoc) and Lit docs for Production Build (articles/hilla/lit/guides/production/production-build.adoc) do not fully reflect the changes required when updating from Hilla 2.x to 24.4.0 as described here: https://vaadin.com/docs/latest/hilla/guides/upgrading.