`azure_tags` are not carried to the `artifactTags` on the Azure proxy resource

## Overview of the Issue

When creating a Compute Gallery Image using Packer, `azure_tags` are correctly applied to the resource on the **owner** subscription, but if the Image Version is fetched from **another** subscription using the [Azure proxy resource](https://learn.microsoft.com/en-us/azure/virtual-machines/share-gallery-direct?tabs=portaldirect#share-a-gallery) the `artifactTags` returned is an empty list.

## Reproduction Steps

1. Create an image with Packer with `azure_tags` set.
2.
```
sig image-version list -r GalleryName -g gallery_resource-group -i imageDefinitionName
[...]
"tags": {
"key1": "value1",
[...]
```
3.
```
az sig image-version list-shared --gallery-unique-name GalleryUniqueID -i imageDefinitionName --location westus2 --shared-to tenant
[
{
"artifactTags": {},
[...]
```

# Plugin and Packer version

Using `FROM docker.io/hashicorp/packer:1.14.2@sha256:250bf3081634255dcabb112ceefd8c77f0b9093e16b21a15516d03a7e996d239 AS packer`

### Simplified Packer Buildfile

```
source "azure-arm" "arm" {
azure_tags = {
key1 = value1
```

Start by tracing how azure_tags move from the Azure image creation path to the Azure proxy resource's artifactTags response; the issue provides reproduction commands for both owner and shared subscriptions. Done means the shared Image Version reports the configured tags instead of an empty artifactTags object, while preserving the existing owner-subscription behavior.

Written by the indexing model from the issue text.