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

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

spec/models/user_spec.rb

@@ -313,9 +313,9 @@ RSpec.describe User, type: :model do
   end
 
   describe 'settings' do
-    it 'is instance of Settings::ScopedSettings' do
+    it 'is instance of UserSettings' do
       user = Fabricate(:user)
-      expect(user.settings).to be_a Settings::ScopedSettings
+      expect(user.settings).to be_a UserSettings
     end
   end
 
@@ -379,16 +379,6 @@ RSpec.describe User, type: :model do
     end
   end
 
-  it_behaves_like 'Settings-extended' do
-    def create!
-      User.create!(account: Fabricate(:account, user: nil), email: 'foo@mastodon.space', password: 'abcd1234', agreement: true)
-    end
-
-    def fabricate
-      Fabricate(:user)
-    end
-  end
-
   describe 'token_for_app' do
     let(:user) { Fabricate(:user) }
     let(:app) { Fabricate(:application, owner: user) }