Feature Request: Support long-form --destination-ip alias for show-next-hop

### Preconditions

- [x] No need to upgrade Python SDK or the Python SDK is ready.

### Related command

az network watcher show-next-hop --resource-group {rg-name} --vm {vm-name} --source-ip {ip} --dest-ip {ip}

### Resource Provider

Microsoft.Network

### Description of Feature or Work Requested

The command `az network watcher show-next-hop` currently supports only the short-form parameter `--dest-ip`.
I am requesting the addition of a long-form parameter `--destination-ip` as an alias for consistency with other
Azure CLI networking commands, which typically provide both short and long parameter names.

This enhancement would improve clarity, readability, and usability without breaking backward compatibility.

### Minimum API Version Required

N/A

### Swagger PR link / SDK link

N/A

### Request Example

_No response_

### Target Date

No strict target date; this is a usability enhancement and not time‑critical.

### PM Contact

N/A

### Engineer Contact

N/A

### Additional context

This request is focused solely on improving parameter naming consistency within the Azure CLI.
The underlying Network Watcher REST API already supports the required fields, and no service-side
changes are needed. Adding the long-form alias `--destination-ip` would align this command with
other networking commands that provide both short and long parameter names.