Install yarn

[yahonda]

Steps to reproduce

• At multipass host

multipass launch 24.04 --cpus 4 --disk 20G --memory 8G --name rails-dev-box --cloud-init ./cloud-init.yaml --timeout 1200
multipass shell rails-dev-box

• At multipass guest

git clone https://github.com/rails/rails
cd rails
bundle update --bundler
bundle install
cd activestorage
bin/test test/javascript_package_test.rb

Expected behavior

All of tests should pass.

Actual behavior

It gets the following error because the yarn is not installed.

Error:
JavascriptPackageTest#test_compiled_code_is_in_sync_with_source_code:
Errno::ENOENT: No such file or directory - yarn
    test/javascript_package_test.rb:15:in `system'
    test/javascript_package_test.rb:15:in `block in test_compiled_code_is_in_sync_with_source_code'
    /home/ubuntu/rails/activesupport/lib/active_support/testing/assertions.rb:49:in `assert_nothing_raised'
    /home/ubuntu/rails/activesupport/lib/active_support/testing/assertions.rb:287:in `_assert_nothing_raised_or_warn'
    /home/ubuntu/rails/activesupport/lib/active_support/testing/assertions.rb:256:in `assert_no_changes'
    test/javascript_package_test.rb:14:in `test_compiled_code_is_in_sync_with_source_code'


bin/rails test /home/ubuntu/rails/activestorage/test/javascript_package_test.rb:6