Prevent installation of Workspaces while Layout Builder is installed

I would prefer that we focus on making Workspaces compatible with Layout Builder in Drupal 10.1.x, rather than declaring them incompatible in code.

That will happen once 📌 Add mechanism to have workspaces skip processing entity types Needs work and ✨ Layout builder overrides on a single content item not allowed in stage when using workspaces Needs work get fixed.