Use core's capybara driver configuration

Solidus core has migrated to using Firefox for headless testing, which seems to
be more stable than Chrome, and uses minimal configuration.

See solidusio/solidus#6230

Author: mamhoff

lib/solidus_dev_support/rspec/capybara.rb

@@ -1,28 +1,4 @@
 # frozen_string_literal: true
 
-# Allow to override the initial windows size
-CAPYBARA_WINDOW_SIZE = ENV.fetch("CAPYBARA_WINDOW_SIZE", "1920x1080").split("x", 2).map(&:to_i)
-CAPYBARA_WINDOW_WIDTH = CAPYBARA_WINDOW_SIZE[0]
-CAPYBARA_WINDOW_HEIGHT = CAPYBARA_WINDOW_SIZE[1]
-
-Capybara.javascript_driver = ENV.fetch("CAPYBARA_JAVASCRIPT_DRIVER", "solidus_chrome_headless").to_sym
-Capybara.default_max_wait_time = 10
-Capybara.server = :puma, {Silent: true} # A fix for rspec/rspec-rails#1897
-
-Capybara.drivers[:selenium_chrome_headless].tap do |original_driver|
-  Capybara.register_driver :solidus_chrome_headless do |app|
-    original_driver.call(app).tap do |driver|
-      driver.resize_window_to(
-        driver.current_window_handle, CAPYBARA_WINDOW_WIDTH, CAPYBARA_WINDOW_HEIGHT
-      )
-    end
-  end
-end
-
-require "capybara-screenshot/rspec"
-
-Capybara::Screenshot.register_driver(:solidus_chrome_headless) do |driver, path|
-  driver.browser.save_screenshot(path)
-end
-
+require "spree/testing_support/capybara_driver"
 require "spree/testing_support/capybara_ext"