Add option to tell packer not to stop the instance

[jeepingben]

/kind feature

Describe the solution you'd like
[I would like to direct packer to not stop the instance I am making when all provisioners are finished
This would be helpful in the case of non-interactive ISO installs where there are no provisioners at all and the installer shuts down the instance. ]

Anything else you would like to add:
[ My current workaround is to use the local-shell provisioner and run a sleep for as long as I think the install would take.

The AWS EBS-surrogate packer plugin uses disable_stop_instance for this: hashicorp/packer-plugin-amazon@74198bc#diff-f97c70941315748d298b576dd2ad777ca6cee404e93aa143b94097542ebf15aeR26 https://github.com/hashicorp/packer-plugin-amazon/blob/e79e7b817c627e10a3c65612e5ab701932fef424/.web-docs/components/builder/ebs/README.md?plain=1#L561]

Environment:

• packer-plugin-nutanix version (use packer plugins installed): /root/.config/packer/plugins/github.com/nutanix-cloud-native/nutanix/packer-plugin-nutanix_v0.9.4_x5.0_linux_amd64
• Packer version (use packer version): Packer v1.11.2
• OS (e.g. from /etc/os-release): PRETTY_NAME="Alpine Linux v3.20" (docker)