Switch using project#security_statistics instead of project_statistics

.../services/security/ingestion/ingest_slice_base_service.rb

...rvices/security/ingestion/tasks/increase_counters_task.rb

ee/app/services/vulnerabilities/create_service_base.rb

ee/app/services/vulnerabilities/manually_create_service.rb

...es/vulnerabilities/removal/remove_from_project_service.rb

...vulnerabilities/starboard_vulnerability_create_service.rb

...s/security/ingestion/tasks/increase_counters_task_spec.rb

.../services/vulnerabilities/manually_create_service_spec.rb

...lnerabilities/removal/remove_from_project_service_spec.rb

...rabilities/starboard_vulnerability_create_service_spec.rb