Move posting defaults to their own preferences sub-category (#35966)

spec/system/settings/preferences/posting_defaults_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Settings preferences posting defaults page' do
+  let(:user) { Fabricate :user }
+
+  before { sign_in user }
+
+  it 'Views and updates user prefs' do
+    visit settings_preferences_posting_defaults_path
+
+    expect(page)
+      .to have_private_cache_control
+
+    check mark_sensitive_field
+
+    expect { save_changes }
+      .to change { user.reload.settings.default_sensitive }.to(true)
+    expect(page)
+      .to have_title(I18n.t('preferences.posting_defaults'))
+  end
+
+  def save_changes
+    click_on submit_button
+  end
+
+  def mark_sensitive_field
+    form_label('defaults.setting_default_sensitive')
+  end
+end