Creating a Secure string parameter in the UI does not allow empty default value

### Severity

P3 - Medium (Minor functionality affected)

### Describe the Bug with repro steps

Expected behavior:
One is able to define a Secure String parameter without default value and save the Logic App definition in UI.

Actual behavior:
A Secure String parameter without default value is not accepted and you can't save the Logic App definition in UI.

Steps to reproduce:
1. Open a consumption Logic App in Azure Portal and select Edit
2. Select Parameters and click "+ Create parameter"
3. Type name for the parameter and select "Secure string" as Type.
4. Observe that there is an error below Default value field: "Must provide value for parameter." and Save icon is grayed out
5. Type something in Default value and observe warning "It is not recommended to set a default value for type 'SecureString' because it will be stored as plain text."

Parameters with empty default values (e.g. "") can be defined in Code view and saved with no problems at all.

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

Consumption (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
-
```

### Screenshots or Videos

### Environment

- Browser: Microsoft Edge Version 141.0.3537.71 (Official build) (64-bit) on Windows 11 23H2

### Additional context

_No response_