Enable the `GraphQL/FieldHashKey` cop

Follow-up of !74789 (diffs).

• 'app/graphql/types/ci/config/job_type.rb'
• 'app/graphql/types/ci/status_action_type.rb'
• 'app/graphql/types/error_tracking/sentry_error_stack_trace_entry_type.rb'
• 'app/graphql/types/packages/helm/dependency_type.rb'