rely on default_projects_modules for seeded project

app/seeders/demo_data/project_seeder.rb

@@ -30,14 +30,12 @@ module DemoData
     # Careful: The seeding recreates the seeded project before it runs, so any changes
     # on the seeded project will be lost.
     def seed_data!
+      # We are relying on the default_projects_modules setting to set the desired project modules
       puts ' ↳ Creating demo project...'
 
       puts '   -Creating/Resetting Demo project'
       project = reset_demo_project
 
-      puts '   -Setting modules.'
-      set_modules(project)
-
       puts '   -Setting members.'
       set_members(project)
 
@@ -84,11 +82,6 @@ module DemoData
       )
     end
 
-    def set_modules(project)
-      project.enabled_module_names += ['timelines']
-      project.enabled_module_names -= ['repository']
-    end
-
     def set_members(project)
       role = Role.find_by(name: I18n.t(:default_role_project_admin))
       user = User.admin.first