fix: run once command list

[tenthirtyam]

Summary

Updates RunOnceCommandList to a slice of strings []string and updates guiRunOnce() to pass "" if no commands are provided. This will ensure that the function addresses each case.

Testing

Basic:

➜  packer-plugin-vsphere git:(fix/run-once-command-list) make generate             
2024/05/09 22:24:23 Copying "docs" to ".docs/"
2024/05/09 22:24:23 Replacing @include '...' calls in .docs/
Compiling MDX docs in '.docs' to Markdown in '.web-docs'...
➜  packer-plugin-vsphere git:(fix/run-once-command-list) make build
➜  packer-plugin-vsphere git:(fix/run-once-command-list) make test
?       github.com/hashicorp/packer-plugin-vsphere      [no test files]
?       github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/common/testing       [no test files]
?       github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/examples/driver      [no test files]
?       github.com/hashicorp/packer-plugin-vsphere/version      [no test files]
ok      github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/clone        2.923s
ok      github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/common       2.614s
ok      github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/driver       7.161s
ok      github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/iso  4.477s
ok      github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/supervisor   8.391s
ok      github.com/hashicorp/packer-plugin-vsphere/post-processor/vsphere       3.897s
ok      github.com/hashicorp/packer-plugin-vsphere/post-processor/vsphere-template      4.728s
➜  packer-plugin-vsphere git:(fix/run-once-command-list) 

Scenarios:

✅ run_once_command_list not provided.
✅ run_once_command_list [] used.
✅ run_once_command_list [""] used.
✅ run_once_command_list ["command1", "command2"] used.

Reference

Closes #419

[lbajolet-hashicorp]

The change looks good to me! I'm a bit surprised at the amount of doc changes that are melded in one commit, there's a lot in there.
Would you be ok to split the PR in two commits? One for the doc improvements, and one for the command fix? That'd be easier to understand the scope of the change here.

[tenthirtyam]

Sure, I can happily split it out today.

[tenthirtyam]

Simplified in 2a31f38, @lbajolet-hashicorp.

[lbajolet-hashicorp]

LGTM, thanks for the split!

[tenthirtyam]

Posted the other half of the split from the original commit.