Minimal APIs: `IFormFile?` parameter still throws 'Unexpected request without body"

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Describe the bug

If I have:
```cs
public static async Task SetCurrentUserProfileImageAsync(IFormFile? image, [other params])
{
}
```
But the client sends the request without a body, it still throws the following even thought the `IFormFile` is nullable:

```
Microsoft.AspNetCore.Http.BadHttpRequestException: 'Unexpected request without body, failed to bind parameter "IFormFile image" from the request body as form.'
```

### Expected Behavior

If the `IFormFile` is optional then it should not throw. In the example above, a null `IFormFile` means the API calll wants to clear the profile image so a body is not required.

### Steps To Reproduce

_No response_

### Exceptions (if any)

_No response_

### .NET Version

10

### Anything else?

_No response_