Output JSON to Blob Storage

### Describe the Bug

We are using Logic App Standard to output to Blob Storage. We have a Logic App that sends a JSON file to blob storage. We are using the Built In Connector and this all must run within a VNet, so the Managed Connector will not work. This has been working fine until recently.

Now when files are output, the Content-Type defaults to application/octet-stream. Previously, this was outputting as application/json; charset=UTF-8. We haven't done any code deployments, but now we are getting different results. The Built In Connector does not have the ability to add a Content-Type, the Managed Connector does, but this is not an option.

How can we output to blob storage and specify the Content-Type? Is this no longer possible or what has changed on the backend to prevent us from using application/json?

### Plan Type

Standard

### Steps to Reproduce the Bug or Issue

Create a new Workflow and add the following:
1. HTTP Request
2. Add a Blob Storage Action - use Upload blob to storage container and use the body of the incoming Request
3. HTTP Response with the results

this will create a entry in Blob Storage with the Content-Type of application/octet-stream

### Workflow JSON

_No response_

### Screenshots or Videos

_No response_

### Additional context

This is now running in a Production environment for a Client, so need to try and understand how we can get this back to how it was previously running.

AB#17367408