Remove free disk space steps from workflows to test if they are necessary

[neubig]

This PR removes the "Free Disk Space (Ubuntu)" step from our GitHub Actions workflows to test if they are still necessary. These steps were taking over 5 minutes to complete.

Changes made:

• Removed the jlumbroso/free-disk-space@main action from dummy-agent-test.yml
• Removed the jlumbroso/free-disk-space@main action from multiple jobs in ghcr-build.yml:
  • ghcr_build_app job
  • ghcr_build_runtime job
  • test_runtime_root job
  • test_runtime_oh job

This is a test to see if our workflows can run successfully without explicitly freeing disk space. If the workflows fail due to disk space issues, we can consider alternative approaches:

1. Use GitHub-hosted runners with more disk space
2. Clean up unnecessary files and caches before running space-intensive tasks
3. Optimize the build process to use less disk space
4. Use a more targeted approach to free disk space by only removing specific tools/packages that we know we do not need

Expected outcomes:

• If the workflows pass: We can keep these changes and benefit from faster CI runs
• If the workflows fail: We will need to explore the alternative approaches listed above

---

To run this PR locally, use the following command:

docker run -it --rm   -p 3000:3000   -v /var/run/docker.sock:/var/run/docker.sock   --add-host host.docker.internal:host-gateway   -e SANDBOX_RUNTIME_CONTAINER_IMAGE=docker.all-hands.dev/all-hands-ai/runtime:2e85489-nikolaik   --name openhands-app-2e85489   docker.all-hands.dev/all-hands-ai/openhands:2e85489

[mamoodi]

Approved but will be good to keep an eye on this as it causes random and hard to track failures.