Bump selenium-webdriver to 4.29.1

This commit bumps the selenium-webdriver to 4.29.1 to address the following error:

```ruby
$ cd actionpack
$ bundle exec rake test
... snip ...

2025-02-26 06:18:09 ERROR Selenium [:selenium_manager] Unsuccessful response (404 Not Found) for URL https://ftp.mozilla.org/pub/firefox/releases/135.0.1/linux-x86_64/en-US/firefox-135.0.1.tar.bz2
2025-02-26 06:18:09 ERROR Selenium Exception occurred: Unsuccessful command executed: ["/home/vscode/.rbenv/versions/3.4.2/lib/ruby/gems/3.4.0/gems/selenium-webdriver-4.27.0/bin/linux/selenium-manager", "--browser", "firefox", "--language-binding", "ruby", "--output", "json"] - Code 65
{"code" => 65, "message" => "Unsuccessful response (404 Not Found) for URL https://ftp.mozilla.org/pub/firefox/releases/135.0.1/linux-x86_64/en-US/firefox-135.0.1.tar.bz2", "driver_path" => "", "browser_path" => ""}
```

Starting from Firefox 135.0, the binaries are  provided in XZ format, replacing the previous BZ2 one.

https://www.mozilla.org/en-US/firefox/135.0/releasenotes/
> Linux binaries are now provided in XZ format, replacing the previous BZ2 format, offering faster unpacking and smaller file sizes.

```
% curl -s -o /dev/null -w "%{http_code}\n" https://ftp.mozilla.org/pub/firefox/releases/135.0.1/linux-x86_64/en-US/firefox-135.0.1.tar.bz2
404

% curl -s -o /dev/null -w "%{http_code}\n" https://ftp.mozilla.org/pub/firefox/releases/135.0.1/linux-x86_64/en-US/firefox-135.0.1.tar.xz
200
```

selenium-webdriver 4.28.0 supports this change. This commit bumps the latest one 4.29.1 since there is no reason to use the older one at Rails CI.
SeleniumHQ/selenium#15115

Author: yahonda

Gemfile.lock

@@ -528,7 +528,7 @@ GEM
     sass-embedded (1.83.4-x86_64-linux-gnu)
       google-protobuf (~> 4.29)
     securerandom (0.4.1)
-    selenium-webdriver (4.27.0)
+    selenium-webdriver (4.29.1)
       base64 (~> 0.2)
       logger (~> 1.4)
       rexml (~> 3.2, >= 3.2.5)