Revert "Fix selenium-webdriver version to avoid bug"

This reverts commit f468994.

After the release of capybara 3.39.1 with a fix for the issue for the
newest selenium-webdriver release, there's no longer the need to lock
the later.

See:

- teamcapybara/capybara#2667
- teamcapybara/capybara#2666
- SeleniumHQ/selenium#12005

Gemfile

@@ -38,7 +38,7 @@ gem 'factory_bot_rails', '>= 4.8', require: false
 group :backend do
   gem 'capybara', '~> 3.13', require: false
   gem 'capybara-screenshot', '>= 1.0.18', require: false
-  gem 'selenium-webdriver', '4.9.0', require: false
+  gem 'selenium-webdriver', require: false
   gem 'webdrivers', require: false
 
   # JavaScript testing