DEV: Remove the use of Capybara::Session#quit (#24978)

Why this change?

This is what `Capybara::Session#quit` does:

```
    def quit
      @driver.quit if @driver.respond_to? :quit
      @document = @driver = nil
      @touched = false
      @server&.reset_error!
    end
```

One notable thing is that it resets server errors which means that any
server errors encountered by a session is cleared. That is not what we
want since it hides errors even though `Capybara.raise_server_errors`
has been set to `true`.

spec/support/system_helpers.rb

@@ -148,10 +148,9 @@ module SystemHelpers
   end
 
   def using_browser_timezone(timezone, &example)
-    using_session(timezone) do |session|
+    using_session(timezone) do
       page.driver.browser.devtools.emulation.set_timezone_override(timezone_id: timezone)
       freeze_time(&example)
-      session.quit
     end
   end