Fix specs ordering related to omniauth stub

The following discussion from !8483 (merged) should be addressed:

• @ayufan started a discussion:

  1) Groups::OmniauthCallbacksController when request hasn't been validated by omniauth middleware prevents authentication
       Failure/Error:
         expect do
           post provider, group_id: group
         end.to raise_error(AbstractController::ActionNotFound)
  
         expected AbstractController::ActionNotFound but nothing was raised
       # ./ee/spec/controllers/groups/omniauth_callbacks_controller_spec.rb:25:in `block (3 levels) in <top (required)>'
  
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  2403 examples, 1 failure, 168 pending
  
  Failed examples:
  
  rspec ./ee/spec/controllers/groups/omniauth_callbacks_controller_spec.rb:22 # Groups::OmniauthCallbacksController when request hasn't been validated by omniauth middleware prevents authentication

  The failure is related to ordering of specs:

  ee/spec/features/users/login_spec.rb
  ee/spec/controllers/groups/omniauth_callbacks_controller_spec.rb