Remove ci_secrets_syntax feature flag

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/243431

ee/app/models/ee/ci/build.rb

@@ -136,7 +136,7 @@ module EE
       end
 
       def ci_secrets_management_available?
-        project.beta_feature_available?(:ci_secrets_management)
+        project.feature_available?(:ci_secrets_management)
       end
 
       override :runner_required_feature_names

ee/changelogs/unreleased/ci-secrets-remove-feature-flags.yml

+---
+title: Add support for reading Vault secrets from CI jobs
+merge_request: 42055
+author:
+type: added

ee/config/feature_flags/licensed/ci_secrets_management.yml

+---
+name: ci_secrets_management
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/42055
+rollout_issue_url:
+group: group::release management
+type: licensed
+default_enabled: true

ee/lib/ee/gitlab/ci/config/entry/job.rb

@@ -12,10 +12,6 @@ module EE
             prepended do
               attributes :secrets
 
-              validations do
-                validates :secrets, absence: { message: 'feature is disabled' }, unless: :secrets_enabled?
-              end
-
               entry :secrets, ::Gitlab::Ci::Config::Entry::Secrets,
                 description: 'Configured secrets for this job',
                 inherit: false
@@ -25,10 +21,6 @@ module EE
             def value
               super.merge({ secrets: secrets_value }.compact)
             end
-
-            def secrets_enabled?
-              ::Gitlab::Ci::Features.secrets_syntax_enabled?
-            end
           end
         end
       end

ee/lib/ee/gitlab/ci/features.rb

-# frozen_string_literal: true
-
-module EE
-  module Gitlab
-    module Ci
-      module Features
-        extend ActiveSupport::Concern
-
-        prepended do
-          def self.secrets_syntax_enabled?
-            ::Feature.enabled?(:ci_secrets_syntax)
-          end
-        end
-      end
-    end
-  end
-end

ee/spec/lib/gitlab/ci/config/entry/job_spec.rb

@@ -10,29 +10,12 @@ RSpec.describe Gitlab::Ci::Config::Entry::Job do
       context 'when has secrets' do
         let(:config) { { script: 'echo', secrets: { DATABASE_PASSWORD: { vault: 'production/db/password' } } } }
 
-        context 'when ci_secrets_syntax feature flag is enabled' do
         before do
-            stub_feature_flags(ci_secrets_syntax: true)
           entry.compose!
         end
 
         it { expect(entry).to be_valid }
       end
-
-        context 'when ci_secrets_syntax feature flag is disabled' do
-          before do
-            stub_feature_flags(ci_secrets_syntax: false)
-            entry.compose!
-          end
-
-          it 'returns an error' do
-            aggregate_failures do
-              expect(entry).not_to be_valid
-              expect(entry.errors).to include 'job secrets feature is disabled'
-            end
-          end
-        end
-      end
     end
 
     context 'when entry value is not correct' do

lib/gitlab/ci/features.rb

@@ -77,5 +77,3 @@ module Gitlab
     end
   end
 end
-
-::Gitlab::Ci::Features.prepend_if_ee('::EE::Gitlab::Ci::Features')