Run action text system tests

[hahmed]

Re-add system tests for action text (ended up reverting https://github.com/rails/buildkite-config/pull/26)

Rails PR that's needed to run the tests https://github.com/rails/rails/pull/47127

To repro, as mentioned in this comment https://github.com/rails/buildkite-config/pull/26#issuecomment-1384864919

git clone https://github.com/rails/rails
cd rails
git clone https://github.com/rails/buildkite-config .buildkite/
RUBY_IMAGE=ruby:3.2 docker-compose -f .buildkite/docker-compose.yml build base
CI=1 docker-compose -f .buildkite/docker-compose.yml run default runner actiontext 'rake test:system'