v1.26.1: Fix regression in wait-for-startup module

What's Changed

GoogleCloudPlatform/guest-agent@5c85572 introduced a change in bootup logging that prevented the community/modules/scripts/wait-for-startup module from detecting the end of a failed startup-script. The new solution has been patched to detect failure on new and old releases of the guest-agent.

Bug fixes 🐞

• Hotfix wait for startup update by @cdunbar13 in #2045

Full Changelog: v1.26.0...v1.26.1