Unable to process template language expressions for resource (Logic App API Connection to Blob Storage)

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[arm-template-retrieve-azure-storage-access-keys](https://github.com/Azure/azure-quickstart-templates/tree/master/demos/arm-template-retrieve-azure-storage-access-keys)

### Issue Details

Bad request details when running the deployment:

```
{
"status": "Failed",
"error": {
"code": "InvalidTemplate",
"message": "Unable to process template language expressions for resource '/subscriptions/1ebbf115-096c-420f-9cde-42cefb07c19f/resourceGroups/demo-logicapp-api-connection-rg/providers/Microsoft.Web/connections/storageconnectionra3e7hsjtbe52' at line '90' and column '9'. 'The template language function 'uri' expects its first argument to be a uri string. The provided value is ''. Please see https://aka.ms/arm-template-expressions/#uri for usage details.'",
"additionalInfo": [
{
"type": "TemplateViolation",
"info": {
"lineNumber": 90,
"linePosition": 9,
"path": ""
}
}
]
}
}
```

### Repro steps (*if necessary, delete otherwise*)
1. Click the blue deploy to Azure button
2. Fill in details. I chose Canada Central for the region and used the filled in values for everything else
3. Error happens when ARM template is trying to create the API Connection

Start with the deployment template in demos/arm-template-retrieve-azure-storage-access-keys and inspect the API Connection resource at line 90. Reproduce the deployment using the listed Canada Central inputs and trace the empty value passed to the uri expression. Done means the Logic App API Connection deploys without the InvalidTemplate error.

Written by the indexing model from the issue text.