fix mem leakage based on leaks tool (still WIP)

common/common-nexa.cpp

@@ -150,6 +150,7 @@ bool load_hparams_and_tensors_from_gguf(const std::string &fname, NexaBaseModel
     }
 
     ggml_free(meta);
+    gguf_free(ctx_gguf);
     return true;
 }
 

examples/qwen2-audio/whisper.cpp

@@ -9467,6 +9467,8 @@ static bool whisper_encoder_load(struct whisper_model_loader *loader, whisper_co
 
     wctx.t_load_us = ggml_time_us() - t_start_us;
 
+    gguf_free(gguf_ctx);
+
     return true;
 }