Azure OpenAI - Upload file with purpose set to "batch"

[agiordimaina]

Describe the bug
Uploading a file with the purpose set to “batch” using Azure OpenAI is failing.

Code

var openAiService = new OpenAIService(new OpenAiOptions()
{
    ApiKey = "{apiKey}",
    ProviderType = ProviderType.Azure,
    DefaultModelId = Models.Gpt_4o_mini,
    ResourceName = "{resourceName}",
    ApiVersion = "2024-07-01-preview",
    DeploymentId = "{deploymentId}"
});

FileUploadResponse result = await openAiFileService.Files.UploadFile("batch", fileContent, "test.jsonl");

Result
The upload fails with the error: “Resource not found”.

Additional context
Using the "2024-07-01-preview" version, you can now upload files with "purpose" set to "batch".
https://learn.microsoft.com/en-us/rest/api/azureopenai/files/upload?view=rest-azureopenai-2024-07-01-preview&tabs=HTTP#purpose

The current URI format used by the library is:
https://{resourceName}.openai.azure.com/openai/deployments/{deploymentId}/files?api-version=2024-07-01-preview

The correct URI format for Azure OpenAI when using purpose set to "batch" should be:
https://{resourceName}.openai.azure.com/openai/files?api-version=2024-07-01-preview

Another issue related to uploading files is that when using ByteArrayContent to upload the file, the header is not being set. This results in the following error:
The file has no or an empty content type specified.