Decompiler is unable to convert templates containing KeyVault secret reference parameters

I am trying to decompile an arm-template but I get the error:
`Decompilation failed with fatal error "Value cannot be null. (Parameter 'value')"`

```
az bicep version
Bicep CLI version 0.4.613 (d826ce8411)
```

This is the arm template:

```json
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"integrationServiceEnvironmentId":{
"type": "string",
"metadata": {
"description": "ResourceId of the ISE"
}
},
"connectionname": {
"type": "string",
"metadata": {
"description": "Name of the connection"
}
},
"serverAddress": {
"type": "string",
"metadata": {
"description": "FTP Server Address"
}
},
"userName": {
"type": "string",
"metadata": {
"description": "User Name"
}
},
"serverPort": {
"type": "int",
"metadata": {
"description": "Provide FTP Server Port"
}
},
"isSSL": {
"type": "bool",
"metadata": {
"description": "Specify if SSL needs to be enabled"
}
},
"isBinaryTransport": {
"type": "bool",
"metadata": {
"description": "Specify if Binary Transport needs to be enabled"
}
},
"disableCertificateValidation": {
"type": "bool",
"metadata": {
"description": "Specify if Certificate Validation needs to be disabled"
}, "defaultValue": "null"
},
"closeConnectionAfterRequestCompletion": {
"type": "bool",
"metadata": {
"description": "Specify if the session should be closed everytime after request completes. Enable if you hit Max Connections limit."
}
},
"keyvaultName": {
"type": "string",
"metadata": {
"description": "Name of the keyvault"
}
},
"keyvaultKey": {
"type": "string",
"metadata": {
"description": "Key of the keyvault secret"
}
}
},
"variables": {
},
"resources": [{
"type": "Microsoft.Resources/deployments",
"apiVersion": "2018-05-01",
"name": "dynamicSecret",
"properties": {
"mode": "Incremental",
"expressionEvaluationOptions": {
"scope": "inner"
},
"parameters": {
"integrationServiceEnvironmentId":{
"value": "[parameters('integrationServiceEnvironmentId')]"
},
"connectionname": {
"value": "[parameters('connectionname')]"
},
"serverAddress": {
"value": "[parameters('serverAddress')]"
},
"userName": {
"value": "[parameters('userName')]"
},
"password": {
"reference": {
"keyVault": {
"id": "[concat(resourceId('Microsoft.KeyVault/vaults', parameters('keyvaultName')))]"
},
"secretName": "[parameters('keyvaultKey')]"
}
},
"serverPort": {
"value": "[parameters('serverPort')]"
},
"isSSL": {
"value": "[parameters('isSSL')]"
},
"isBinaryTransport": {
"value": "[parameters('isBinaryTransport')]"
},
"disableCertificateValidation": {
"value": "[parameters('disableCertificateValidation')]"
},
"closeConnectionAfterRequestCompletion": {
"value": "[parameters('closeConnectionAfterRequestCompletion')]"
}
},

"template": {
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"integrationServiceEnvironmentId": {
"type": "string",
"metadata": {
"description": "ResourceId of the ISE"
}
},
"connectionname": {
"type": "string",
"metadata": {
"description": "Name of the connection"
}
},
"serverAddress": {
"type": "string",
"metadata": {
"description": "FTP Server Address"
}
},
"userName": {
"type": "string",
"metadata": {
"description": "FTP User Name"
}
},
"password": {
"type": "string",
"metadata": {
"description": "FTP password"
}
},
"serverPort": {
"type": "int",
"metadata": {
"description": "Provide FTP Server Port"
}
},
"isSSL": {
"type": "bool",
"metadata": {
"description": "Specify if SSL needs to be enabled"
}
},
"isBinaryTransport": {
"type": "bool",
"metadata": {
"description": "Specify if Binary Transport needs to be enabled"
}
},
"disableCertificateValidation": {
"type": "bool",
"metadata": {
"description": "Specify if Certificate Validation needs to be disabled"
}
},
"closeConnectionAfterRequestCompletion": {
"type": "bool",
"metadata": {
"description": "Specify if the session should be closed everytime after request completes. Enable if you hit Max Connections limit."
}
}
},
"resources": [{
"type": "Microsoft.Web/connections",
"apiVersion": "2016-06-01",
"location": "[resourceGroup().location]",
"name": "[parameters('connectionname')]",
"properties": {
"displayName": "[parameters('connectionname')]",
"customParameterValues": {},
"api": {
"id": "[concat(parameters('integrationServiceEnvironmentId') , '/managedApis/ftp')]"
},
"parameterValues": {
"serverAddress": "[parameters('serverAddress')]",
"userName": "[parameters('userName')]",
"password": "[parameters('password')]",
"serverPort": "[parameters('serverPort')]",
"isSSL": "[parameters('isSSL')]",
"isBinaryTransport": "[parameters('isBinaryTransport')]",
"disableCertificateValidation": "[parameters('disableCertificateValidation')]",
"closeConnectionAfterRequestCompletion": "[parameters('closeConnectionAfterRequestCompletion')]"
}
}
}],
"outputs": {}
}
}
}]
}

```

Start by reproducing the failure with the supplied ARM template and the reported Bicep CLI version using the decompile command. Trace the decompiler path handling nested deployment parameters and Key Vault references; done means the template no longer fails with a null-value error and produces valid Bicep output.

Written by the indexing model from the issue text.