Code review comment for ~alextu/pc-enablement/+git/oem-scripts:recovery-from-iso-inject-stella-on-somverville-img

Test pass with 202104-28974. One question of dell-bto-focal-fossa-edge-alloem-init-X170-20211019-16.iso, what is the expected user name of this image? I see u and ubuntu both exist. When OS startup, I observe u as login user. `user_on_target` expects "ubuntu".