Bicep-generated nested templates causing many 'Cannot bind argument to parameter TemplateText' errors in Marketplace tests

### Background
- We're using the latest arm-ttk alongside our Azure application offer per Partner Center requirements.
- We generate our mainTemplate.json from Azure Bicep files, which create nested templates

### Issues
Broadly, we see a littany of issues that we think are related to nested templates. They most commonly surface by erroring certain tests with a `Cannot bind argument to parameter 'TemplateText' because it is (an empty |null)` but there are also unreferenced variable or empty property warnings.

But we also see multiple outright errors during ingestion that usually point to lines 428, 711, 775:

```
InvalidOperation: /Users/nickspagnola/Development/Projects/arm-ttk/arm-ttk/Test-AzTemplate.ps1:428
Line |
428 | … $location.Line += $testOut.InnerTemplateLocation.Line - 1 …|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| The property 'Line' cannot be found on this object. Verify that the property exists and can be set.

Expand-AzTemplate: /Users/nickspagnola/Development/Projects/arm-ttk/arm-ttk/Test-AzTemplate.ps1:711
Line |
711 | … $expandedTemplate =Expand-AzTemplate -TemplatePath $templatePath|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| Could not extract inner templates for './working-app'.

Write-Error: /Users/nickspagnola/Development/Projects/arm-ttk/arm-ttk/Test-AzTemplate.ps1:775
Line |
775 | Test-FileList # we just call it directly.|
~~~~~~~~~~~~~
| Could not extract inner templates for './working-app'.
```

We amended the arm-ttk scripts to print out which template was responsible for the error, and its typically in areas where our bicep modules are nested two or three times deep.

### Impact
While we think this is a broader issue related to nested templates, it just so happens that it is hitting a required Marketplace test- Location Should Not Be Hardcoded. But we do not hardcode any locations. I've changed any references to locations (like in urls in deployment scripts, azure app config key values, etc) to use only the top level parameter provided by the createUiDefinition.json. There are no words in our mainTemplate.json that use an azure region. But the error persists.

Thank you!