[Bug]: Parameters array format expects "default" to be string

### What happened?

DAB expects the `default` parameter in the new parameters array format to be of type string.
Types other than string fail DAB to start, besides documentation states datatype "any" and the configuration-file validates successful against the JSON-Schema:

```
{
"$schema": "https://github.com/Azure/data-api-builder/releases/download/v2.0.8/dab.draft.schema.json",
...
"entities": {
"test": {
"source": {
"object": "dbo.sp_Test",
"type": "stored-procedure",
"parameters": [
{
"name": "Id",
"default": 0
},
{
"name": "InitValue",
"value": 0
},
{
"name": "Name",
"value": "test"
}
]
},
"rest": {
"enabled": true,
"methods": [
"post"
]
},
...
```

### Version

2.0.8

### What database are you using?

Azure SQL

### What hosting model are you using?

AppService

### Which API approach are you accessing DAB through?

REST

### Relevant log output

```Text
2026-06-10T14:12:33.1708776Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:33.1708897Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:33.1708941Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:33.1709014Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:33.1709064Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:33.1709103Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:33.1709143Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:33.1709176Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:33.1771964Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:34.7860448Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:34.7861245Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:35.2621692Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:35.2624784Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
2026-06-10T14:12:35.5071225Z fail: Azure.DataApiBuilder.Config.FileSystemRuntimeConfigLoader[0]
2026-06-10T14:12:35.5072024Z Deserialization of the configuration file failed. The JSON value could not be converted to System.String. Path: $.parameters[0].default | LineNumber: 6 | BytePositionInLine: 24.
```

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct