fix(ubuntu): restablish empty default grub cmdline after cloud-init install

[sticky-note]

Summary of Pull Request

I ran into #981 today, it seems to come from GRUB_CMDLINE_LINUX_DEFAULT being set on packer template provisioning via cloud-init installer.
It is set by packer boot_command on kernel cmdline arguments and tell cloud-init to use a specific DataSource (nocloud-net or nocloud) and the installer persists these arguments on grub configuration in /etc/default/grub.
It it the reason why cloud-init does not read VMware DataSource.

I ended up with this Pull Request to restablish an empty GRUB_CMDLINE_LINUX_DEFAULT as late_command

It works on my side

Tested on Ubuntu 22.04 LTS

Hope it'll help someone.

Type of Pull Request

• This is a bugfix. type/bug
• This is an enhancement or feature. type/feature or type/enhancement
• This is a documentation update. type/docs
• This is a refactoring update. type/refactor
• This is a chore. type/chore
• This is something else.
  Please describe:

Related to Existing Issues

Closes #981

Test and Documentation Coverage

• Tests have been completed.
• Documentation has been added or updated.

Breaking Changes?

• Yes, there are breaking changes.
• No, there are no breaking changes.

[tenthirtyam]

@sticky-note - please amend your commit with the required sign-off. Once updated, we'll be able to review and proceed.

Thanks!

Ryan Johnson
Distinguished Engineer, VMware by Broadcom

[tenthirtyam]

@sticky-note - if you are uncomfortable adding the sign-off, please let me know and I'll add the fix seperately.