Remove block_namespace_serialization feature flag

Changelog: changed

app/models/namespace.rb

@@ -661,10 +661,6 @@ class Namespace < ApplicationRecord
     # Use SHA2 of `traversal_ids` to account for moving a namespace within the same root ancestor hierarchy.
     "namespaces:{#{traversal_ids.first}}:first_auto_devops_config:#{group_id}:#{Digest::SHA2.hexdigest(traversal_ids.join(' '))}"
   end
-
-  def allow_serialization?(options = nil)
-    Feature.disabled?(:block_namespace_serialization, self, default_enabled: :yaml) || super
-  end
 end
 
 Namespace.prepend_mod_with('Namespace')

config/feature_flags/development/block_namespace_serialization.yml

----
-name: block_namespace_serialization
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/82661
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/355553
-milestone: '14.9'
-type: development
-group: group::global search
-default_enabled: false

spec/models/namespace_spec.rb

@@ -2235,13 +2235,5 @@ RSpec.describe Namespace do
     let(:object) { build(:namespace) }
 
     it_behaves_like 'blocks unsafe serialization'
-
-    context 'when feature flag block_namespace_serialization is disabled' do
-      before do
-        stub_feature_flags(block_namespace_serialization: false)
-      end
-
-      it_behaves_like 'allows unsafe serialization'
-    end
   end
 end