[CI] Remove a few predefined runner files before releasing npm packages

[adamziel]

Motivation for the change, related issues

Updates the publish-npm-packages.yml job to prevent the CI runner from running out of disk space.

https://github.com/WordPress/wordpress-playground/actions/runs/18473424159/job/52632469981

lerna ERR! 
lerna ERR! lerna ENOSPC: no space left on device, write

Implementation details

Removes a bunch of large files that seem to be present at the start of the job:

            - name: Free up runner disk space
              shell: bash
              run: |
                  set -euo pipefail
                  echo "Disk usage before cleanup:"
                  df -h
                  sudo rm -rf /usr/local/lib/android
                  sudo rm -rf /usr/share/dotnet
                  sudo rm -rf "$AGENT_TOOLSDIRECTORY"
                  sudo rm -rf /opt/ghc
                  sudo rm -rf /opt/hostedtoolcache/CodeQL
                  echo "Disk usage after cleanup:"
                  df -h

Testing Instructions (or ideally a Blueprint)

GitHub and testing CI PRs? Haha. Nope. Merge, run the job, hope for the best.