naming : normalize the name of callback-related identifiers

ggml-ci

tests/test-model-load-cancel.cpp

@@ -17,7 +17,7 @@ int main(int argc, char *argv[] ) {
     llama_backend_init();
     auto params = llama_model_params{};
     params.use_mmap = false;
-    params.progress_callback = [](float progress, void * ctx){
+    params.cb_progress = [](float progress, void * ctx){
         (void) ctx;
         return progress > 0.50;
     };