Change user settings to be stored in a more optimal way (#23630)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

spec/models/user_settings/namespace_spec.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe UserSettings::Namespace do
+  subject { described_class.new(name) }
+
+  let(:name) { :foo }
+
+  describe '#setting' do
+    before do
+      subject.setting :bar, default: 'baz'
+    end
+
+    it 'adds setting to definitions' do
+      expect(subject.definitions[:'foo.bar']).to have_attributes(name: :bar, namespace: :foo, default_value: 'baz')
+    end
+  end
+
+  describe '#definitions' do
+    it 'returns a hash' do
+      expect(subject.definitions).to be_a Hash
+    end
+  end
+end