Remove ci_runner_manager_runtime_features feature flag

Changelog: other

config/feature_flags/gitlab_com_derisk/ci_runner_manager_runtime_features.yml

----
-name: ci_runner_manager_runtime_features
-feature_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/519966
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/181817
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/520116
-milestone: '17.10'
-group: group::ci platform
-type: gitlab_com_derisk
-default_enabled: false

lib/api/ci/helpers/runner.rb

@@ -242,8 +242,6 @@ def get_runner_config_from_request
         end
 
         def get_runner_features_from_request
-          return {} unless Feature.enabled?(:ci_runner_manager_runtime_features, current_runner)
-
           { runtime_features: attributes_for_keys(%w[features], params['info'])['features'] }.compact
         end