az gallery service-artifact | missing examples in reference content

### Describe the bug

### Bug category:
**Missing information**

### Request:

The [Azure CLI reference guidelines](https://github.com/Azure/azure-cli/blob/dev/doc/reference_doc_guidelines.md#examples) specifiy at least two examples for each command. Please review the Azure CLI reference guidelines for [examples](https://github.com/Azure/azure-cli/blob/dev/doc/reference_doc_guidelines.md#examples) and [parameters](https://github.com/Azure/azure-cli/blob/dev/doc/reference_doc_guidelines.md#parameters) and add missing content to your source code.

If a parameter accepts JSON content, provide a JSON example in the parameter long or short summary, or in a separate code block.

### Issue summary:
Understanding that not all “create” commands directly generate Microsoft revenue, every “create” or “add” minimally make a revenue-producing Azure resource possible. Consequently, **create commands are the most important examples to add.** Of secondary importance are reference commands with complex parameters (JSON, YAML, URLs, complex Azure resource IDs, multi-valued lists, key:value pairs, conditional parameters, parameter pairs ...).

### Command list with no examples:

| Reference name | Parameter count | is Create |
|-|-|-|
| [az gallery service-artifact create](https://docs.microsoft.com/cli/azure/gallery/service-artifact#az-gallery-service-artifact-create) | 9 | **yes** |
| [az gallery service-artifact get](https://docs.microsoft.com/cli/azure/gallery/service-artifact#az-gallery-service-artifact-get) | 6 | |
| [az gallery service-artifact list](https://docs.microsoft.com/cli/azure/gallery/service-artifact#az-gallery-service-artifact-list) | 2 | |
| [az gallery service-artifact update](https://docs.microsoft.com/cli/azure/gallery/service-artifact#az-gallery-service-artifact-update) | 15 | |
| [az gallery service-artifact wait](https://docs.microsoft.com/cli/azure/gallery/service-artifact#az-gallery-service-artifact-wait) | 13 | |

### Related command

az gallery service-artifact

### Errors

n/a

### Issue script & Debug output

n/a

### Expected behavior

n/a

### Environment Summary

Azure CLI 2.63.0

### Additional context

_No response_