Remove block_project_serialization feature flag

Changelog: changed

app/models/project.rb

@@ -3043,10 +3043,6 @@ class Project < ApplicationRecord
       Projects::SyncEvent.enqueue_worker
     end
   end
-
-  def allow_serialization?(options = nil)
-    Feature.disabled?(:block_project_serialization, self, default_enabled: :yaml) || super
-  end
 end
 
 Project.prepend_mod_with('Project')

config/feature_flags/development/block_project_serialization.yml

----
-name: block_project_serialization
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/81900
-rollout_issue_url:
-milestone: '14.9'
-type: development
-group: group::workspace
-default_enabled: false

spec/models/project_spec.rb

@@ -8026,14 +8026,6 @@ RSpec.describe Project, factory_default: :keep do
     let(:object) { build(:project) }
 
     it_behaves_like 'blocks unsafe serialization'
-
-    context 'when feature flag block_project_serialization is disabled' do
-      before do
-        stub_feature_flags(block_project_serialization: false)
-      end
-
-      it_behaves_like 'allows unsafe serialization'
-    end
   end
 
   private