`az.cmd pipelines variable-group create` fails on windows if description contains spaces

# Describe the bug

Trying to create variable group fails because description argument contains spaces.
Works well on `ubuntu-latest` image.

### Command
`az.cmd pipelines variable-group create`

### Error

```
'C:\Program' is not recognized as an internal or external command,
operable program or batch file.
```

# To reproduce

- configure organization `az.cmd devops configure -d organization=$(System.CollectionUri)`
- configure project `az.cmd devops configure -d project=$(System.TeamProjectId)`
- `az.cmd pipelines variable-group create --name "mygroup_name" --variables "variable=value" --authorize true --description "description with spaces"`

# Expected Behavior

Should succeed and create the variable group

# Environment Summary

```
OS windows-2019
---------------------------------------------------
Task Bash
Version 3.163.1
---------------------------------------------------
azure-cli 2.3.0 *

command-modules-nspkg 2.0.3
core 2.3.0 *
nspkg 3.0.4
telemetry 1.0.4

Extensions:
azure-devops 0.17.0
```

Start by reproducing `az.cmd pipelines variable-group create` on Windows with the quoted description shown in the issue, then trace the command entry point handling `--description`. Done means the command succeeds when the description contains spaces and still creates the variable group; verify the reported Linux behavior remains unaffected.

Written by the indexing model from the issue text.