Customer feedback | az netappfiles volume create | `--usage-threshold` is in gigabytes, not bytes

### Describe the bug

This GitHub issues is being created from UUF azDO [#294906](https://dev.azure.com/msft-skilling/Content/_workitems/edit/294906).
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### Engineering request
* If the customer feedback is correct, please update the `--usage-threshold` parameter `shot-summary` to indicate gigabytes

### Customer feedback
Title:
az netappfiles volume | Microsoft Learn

Verbatim:
The --usage-threshold under az netappfiles volume create states that the number is in bytes. In testing, that is incorrect. It is actually in gigabytes.

Verbatim Id:
4d071fb3-c054-ef11-a316-00224805c0b0

Live URL:
https://learn.microsoft.com/en-us/cli/azure/netappfiles/volume

GitHub URL:
https://github.com/MicrosoftDocs/azure-docs-cli/blob/live/latest/docs-ref-autogen/netappfiles/volume.yml

### Related command

az netappfiles volume create

### Errors

.

### Issue script & Debug output

.

### Expected behavior

.

### Environment Summary

Azure CLI 2.65.0

### Additional context

_No response_