regression: Deployment: if no parameter file is chosen, should ask for unspecified parameter values but doesn't

Reported through documentation users: https://github.com/MicrosoftDocs/azure-docs/issues/113981

REPRO:
1) Deploy the following bicep file:
```bicep
param p1 int
```
- for "Select a parameter file", select "None"
!) does not ask for a value for p1 and instead deployment just fails:
```
{"error":{"code":"InvalidTemplate","message":"Deployment template validation failed: 'The value for the template parameter 'p1' at line '1' and column '545' is not provided. Please see https://aka.ms/arm-create-parameter-file for usage details.'.","additionalInfo":[{"type":"TemplateViolation","info":{"lineNumber":1,"linePosition":545,"path":"properties.template.parameters.p1"}}]}}
```
NOTE: This doesn't repro if you instead specify a parameter file, even if it has no values, e.g.:
```json
{
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentParameters.json#",
"contentVersion": "1.0.0.0",
"parameters": {
}
}
```