Update EE projects controller when show_projects? gets removed

The following discussion from !13345 (merged) should be addressed:

• @mayra-cabrera started a discussion: (+8 comments)

  Seems show_projects? it's scheduled to be removed at some point. Should we use another method or logic for this? 🤔

Currently ee/app/controllers/ee/dashboard/projects_controller.rb uses the show_projects? helper which will be deprecated soon. Once show_projects? is removed, need to refactor the logic used in ee/app/controllers/ee/dashboard/projects_controller.rb