Clean mock_deployment_service references as model was removed

The model was removed in 07e8072f.

.rubocop_manual_todo.yml

@@ -1682,7 +1682,6 @@ Gitlab/NamespacedClass:
     - 'app/models/project_services/mattermost_slash_commands_service.rb'
     - 'app/models/project_services/microsoft_teams_service.rb'
     - 'app/models/project_services/mock_ci_service.rb'
-    - 'app/models/project_services/mock_deployment_service.rb'
     - 'app/models/project_services/mock_monitoring_service.rb'
     - 'app/models/project_services/monitoring_service.rb'
     - 'app/models/project_services/open_project_service.rb'

app/models/project.rb

@@ -213,7 +213,6 @@ class Project < ApplicationRecord
   has_one :external_wiki_service
   has_one :prometheus_service, inverse_of: :project
   has_one :mock_ci_service
-  has_one :mock_deployment_service
   has_one :mock_monitoring_service
   has_one :microsoft_teams_service
   has_one :packagist_service

spec/lib/gitlab/import_export/all_models.yml

@@ -395,7 +395,6 @@ project:
 - ewm_service
 - external_wiki_service
 - mock_ci_service
-- mock_deployment_service
 - mock_monitoring_service
 - forked_to_members
 - forked_from_project