Improve test driver registration and sass configuration

- Apply consistent driver registration pattern across all drivers
- Force re-register drivers to ensure fresh configuration in tests
- Remove unnecessary empty includePaths from sass-loader options
- Let Shakapacker handle default sass include paths

These changes improve code consistency and prevent potential issues with overriding Shakapacker defaults.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

config/webpack/commonWebpackConfig.js

@@ -42,10 +42,7 @@ if (sassLoaderIndex !== -1) {
     scssRule.use[sassLoaderIndex] = {
       loader: sassLoader,
       options: {
-        api: 'modern',
-        sassOptions: {
-          includePaths: []
-        }
+        api: 'modern'
       }
     };
   } else {

spec/support/driver_registration.rb

@@ -2,27 +2,29 @@
 
 module DriverRegistration
   def self.register_selenium_chrome
-    return if @selenium_chrome_registered
+    # Force re-register to ensure our configuration is used
+    Capybara.drivers.delete(:selenium_chrome)
 
     Capybara.register_driver :selenium_chrome do |app|
       Capybara::Selenium::Driver.new(app, browser: :chrome)
     end
+
     Capybara::Screenshot.register_driver(:selenium_chrome) do |js_driver, path|
       js_driver.browser.save_screenshot(path)
     end
-    @selenium_chrome_registered = true
   end
 
   def self.register_selenium_firefox
-    return if @selenium_firefox_registered
+    # Force re-register to ensure our configuration is used
+    Capybara.drivers.delete(:selenium_firefox)
 
     Capybara.register_driver :selenium_firefox do |app|
       Capybara::Selenium::Driver.new(app, browser: :firefox)
     end
+
     Capybara::Screenshot.register_driver(:selenium_firefox) do |js_driver, path|
       js_driver.browser.save_screenshot(path)
     end
-    @selenium_firefox_registered = true
   end
 
   def self.register_selenium_chrome_headless