fix(packer/linux): power off bootstrap failure when IMDS has no instance id or IMDS is unreachable

[Yashprime1]

Issue faced -

Cloud-init v. 25.2-0ubuntu1~24.04.1 running 'modules:config' at Mon, 27 Apr 2026 04:14:03 +0000. Up 23.72 seconds.
Cloud-init v. 25.2-0ubuntu1~24.04.1 running 'modules:final' at Mon, 27 Apr 2026 04:14:06 +0000. Up 26.74 seconds.
curl: (7) Failed to connect to 169.254.169.254 port 80 after 0 ms: Couldn't connect to server
curl: (7) Failed to connect to 169.254.169.254 port 80 after 0 ms: Couldn't connect to server
curl: (7) Failed to connect to 169.254.169.254 port 80 after 0 ms: Couldn't connect to server
curl: (7) Failed to connect to 169.254.169.254 port 80 after 0 ms: Couldn't connect to server

Parameter validation failed:
Invalid length for parameter InstanceId, value: 0, valid min length: 1
2026-04-27 04:14:10,619 - cc_scripts_user.py[WARNING]: Failed to run module scripts_user (scripts in /var/lib/cloud/instance/scripts)
2026-04-27 04:14:10,633 - log_util.py[WARNING]: Running module scripts_user (<module 'cloudinit.config.cc_scripts_user' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_scripts_user.py'>) failed

[DamjanBecirovic]

/sem-approve

[DamjanBecirovic]

Hi @Yashprime1, thanks for the contribution.
The issue that was breaking the CI pipeline was fixed on the master branch.
Can you please rebase this PR so we can merge it once the CI pipeline passes?