Fix occurrences of the prompt callback being incorrectly specified, or
the response callback's prototype being incorrectly used in its place.
Signed-off-by: Juuso Alasuutari <juuso.alasuutari@gmail.com>
Fixes the bug where llmodel_model_create prints "Invalid model file" even though the model is loaded correctly. Credits and thanks to @serendipity for the fix.