Customer feedback | az network application-gateway routing-rule | optional parameter `--priority` is required!

### Describe the bug

This customer feedback is being moved from azDO UUF [#266389](https://dev.azure.com/msft-skilling/Content/_workitems/edit/266389).
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### Engineering request
* Add more information to `--priority` parameter that communicates to the customer that any optional parameter is conditional when {something is true}. Here's an example: `Priority of the routing rule. Supported SKU tiers are Standard_v2, WAF_v2. This parameter is REQUIRED when {something is true}.`

### Customer feedback
Title:
az network application-gateway routing-rule | Microsoft Learn

Verbatim:
"--priority" is a mandatory parameter not optional

Verbatim Id:
0e566912-0a2f-ef11-840a-00224804e99d

Live URL:
https://learn.microsoft.com/en-us/cli/azure/network/application-gateway/routing-rule

GitHub URL:
https://github.com/MicrosoftDocs/azure-docs-cli/blob/live/latest/docs-ref-autogen/network/application-gateway/routing-rule.yml

### Related command

az network application-gateway routing-rule

### Errors

.

### Issue script & Debug output

.

### Expected behavior

.

### Environment Summary

Azure CLI 2.65.0

### Additional context

_No response_