Clean up validate_release_description_length feature flag

This commit cleans up the feature flag.

app/models/release.rb

@@ -24,7 +24,7 @@ class Release < ApplicationRecord
   before_create :set_released_at
 
   validates :project, :tag, presence: true
-  validates :description, length: { maximum: Gitlab::Database::MAX_TEXT_SIZE_LIMIT }, if: :should_validate_description_length?
+  validates :description, length: { maximum: Gitlab::Database::MAX_TEXT_SIZE_LIMIT }, if: :description_changed?
   validates_associated :milestone_releases, message: -> (_, obj) { obj[:value].map(&:errors).map(&:full_messages).join(",") }
   validates :links, nested_attributes_duplicates: { scope: :release, child_attributes: %i[name url filepath] }
 
@@ -102,11 +102,6 @@ class Release < ApplicationRecord
 
   private
 
-  def should_validate_description_length?
-    description_changed? &&
-      ::Feature.enabled?(:validate_release_description_length, project, default_enabled: :yaml)
-  end
-
   def actual_sha
     sha || actual_tag&.dereferenced_target
   end

changelogs/unreleased/cleanup-validate_release_description_length-feature-flag.yml

+---
+title: Validate release description length
+merge_request: 60892
+author:
+type: changed

config/feature_flags/development/validate_release_description_length.yml

----
-name: validate_release_description_length
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/60380
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/329192
-milestone: '13.12'
-type: development
-group: group::release
-default_enabled: false

spec/models/release_spec.rb

@@ -48,18 +48,6 @@ RSpec.describe Release do
         expect(release.errors.full_messages)
           .to include("Description is too long (maximum is #{Gitlab::Database::MAX_TEXT_SIZE_LIMIT} characters)")
       end
-
-      context 'when validate_release_description_length feature flag is disabled' do
-        before do
-          stub_feature_flags(validate_release_description_length: false)
-        end
-
-        it 'does not create a validation error' do
-          release.validate
-
-          expect(release.errors.full_messages).to be_empty
-        end
-      end
     end
 
     context 'when a release is tied to a milestone for another project' do