fix(@embark/cmd_controller): don't try to load pipeline module group in build cmd
fix(@embark/cmd_controller): don't try to load pipeline module group in build cmd

We've made the `basic-pipeline` optional in https://github.com/embarklabs/embark/commit/948956ab1f7fde154e4a4a36c58cfa677ecff9c6 but are still
trying to load the pipeline module group in inside the `build` cmd.
This breaks at runtime as no such module group exists anymore.

iurimatias/embark-framework,iurimatias/embark-framework