[BUG] [Experimental] Runtime values in tags and sku

### Existing rule

_No response_

### Description of the issue

Originally reported https://github.com/microsoft/PSRule/issues/3425

When using the new experimental feature in Bicep from 0.46.1: https://github.com/Azure/bicep/releases
([Experimental] Runtime values in tags and sku)
```
resource example 'Microsoft...' = {
name: 'example'
location: resourceGroup().location
sku: {
name: this.existingResource().?sku.name ?? 'Standard'
}
tags: this.existingResource().?tags ?? {}
}
```

### Error messages

Exception calling "GetBicepParamResources" with "2" argument(s): "Unable to expand resources because the source file '/home/vsts/work/1/s/main.bicep' was not valid. The deployment 'root/2026-08-07_14.45' with symbolic name 'hubResourceGroup' failed. An error occurred evaluating expression '[if(parameters('keepExistingTags'), union(coalesce(tryGet(target('full'), 'tags'), createObject()), parameters('tags')), parameters('tags'))]' line 701 at path 'tags'. The function "target" was not found."

### Reproduction

Create a bicep file containing the new function:
```
resource example 'Microsoft...' = {
name: 'example'
location: resourceGroup().location
sku: {
name: this.existingResource().?sku.name ?? 'Standard'
}
tags: this.existingResource().?tags ?? {}
}
```

### Version of PSRule

2.9.0

### Version of PSRule for Azure

_No response_

### Additional context

Azure DevOps Microsoft Hosted Agent using the latest version of Linux, running in a PowerShell task using the latest version of bicep (0.46.1)

The payload names GetBicepParamResources and a reproducible Bicep example, but no repository file or test. Start by reproducing the example with Bicep 0.46.1 and trace the expansion failure around runtime values in tags and sku; done means the example expands without the missing "target" function error.

Written by the indexing model from the issue text.