Parameters are lost when trying new Logix Apps Experience

### Severity

P3 - Medium (Minor functionality affected)

### Describe the Bug with repro steps

Expected Behavior:
- Existing Parameters are displayed, list is editable and parameters are referenceable in the workflow
Actual Behavior:
- No parameters exist in the list

Steps to Reproduce:
- Create a stateful or Autonomous Agents workflow
- Add 1 one or more parameters
- Add 1 or more actions
- Click the Enable Preview button to use the new Logic Apps experience
- Check the parameters:

### What type of Logic App Is this happening in?

Standard (Portal)

### Are you experiencing a regression?

_No response_

### Which operating system are you using?

Windows

### Did you refer to the TSG before filing this issue? https://aka.ms/lauxtsg

Yes

### Workflow JSON

```json
{
"definition": {
"$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
"contentVersion": "1.0.0.0",
"actions": {
"Agent": {
"type": "Agent",
"inputs": {
"parameters": {
"deploymentId": "gpt-4.1",
"messages": [
{
"role": "system",
"content": "test"
}
],
"agentModelType": "AzureOpenAI",
"agentModelSettings": {
"agentHistoryReductionSettings": {
"agentHistoryReductionType": "maximumTokenCountReduction",
"maximumTokenCount": 128000
},
"deploymentModelProperties": {
"name": "gpt-4.1",
"format": "OpenAI",
"version": "2025-04-14"
}
}
},
"modelConfigurations": {
"model1": {
"referenceName": "agent"
}
}
},
"tools": {},
"runAfter": {},
"limit": {
"count": 100
}
}
},
"outputs": {},
"triggers": {
"When_an_HTTP_request_is_received": {
"type": "Request",
"kind": "Http"
}
}
},
"kind": "Stateful"
}
```

### Screenshots or Videos

_No response_

### Environment

- Browser: Microsoft Edge for Business Version 146.0.3856.84

### Additional context

_No response_