I am sending a stream from an IFormFile, but I am getting the following error

### Expected Behaviour

Generate PDF from docx in IFormFile

### Actual Behaviour
Error:

### Reproduce Scenario (including but not limited to)

#### Steps to Reproduce

#### Platform and Version
.NET 7 in macOS 13.5 with Apple Sillicon

#### Sample Code that illustrates the problem
```
// Initial setup, create credentials instance.
Credentials credentials = Credentials.ServicePrincipalCredentialsBuilder()
.WithClientId("")
.WithClientSecret("")
.Build();

ExecutionContext executionContext = ExecutionContext.Create(credentials);
DocumentMergeOptions documentMergeOptions = new DocumentMergeOptions(jsonObject, OutputFormat.PDF);
DocumentMergeOperation documentMergeOperation = DocumentMergeOperation.CreateNew(documentMergeOptions);

using var stream = new MemoryStream();
await file.CopyToAsync(stream);
FileRef source = FileRef.CreateFromStream(stream, CreatePDFOperation.SupportedSourceFormat.DOCX.GetMediaType());
documentMergeOperation.SetInput(source);

FileRef result = documentMergeOperation.Execute(executionContext);
await using Stream outputStream = PrepareOutputStream();
result.SaveAs(outputStream);
_logger.LogInfo("Moving this temporary file to output stream.");
```

#### Logs taken while reproducing problem

Start with the supplied sample-code path at FileRef.CreateFromStream and DocumentMergeOperation.Execute, then compare it with the .NET 7 sample application's handling of the IFormFile stream. Capture the full error and complete reproduction steps first; done means reproducing the failure and identifying a documented correction or confirmed SDK issue.

Written by the indexing model from the issue text.