Setup action fails because of missing yarn

[WTPOptAxe]

I'm trying to setup a self hosted runner that builds TypeScript applications.

https://github.com/actions/actions-runner-controller/blob/aac811f210782d1a35e33ffcfe12db69ebe8e447/docs/about-arc.md states

To install additional software, it is recommended to use the corresponding setup actions. For instance, actions/setup-java for Java or actions/setup-node for Node.

However actions/setup-node fails with

Error: Unable to locate executable file: yarn. Please verify either the file path exists or the file can be found within a directory specified by the PATH environment variable. Also check the file mode to verify the file is executable.

What's the right way to make this work? I've created my own image from summerwind/actions-runner:ubuntu-22.04 but it's not clear to me how to use this in my RunnerDeployment