Re-running the ECE upgrade

By default, re-running the elastic-cloud-enterprise.sh upgrade command resumes the previous ECE upgrade process. However, if your previous ECE upgrade attempt got stuck (for example, due to infrastructure problems, a host going offline, or similar) and re-attempting the upgrade still results in the upgrade process being blocked, run elastic-cloud-enterprise.sh upgrade --force-upgrade to ensure that any existing upgrade state gets cleared before starting the new ECE upgrade process.