MiniCPM-V 2.6 memory leak occurred !!!

# Prerequisites

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- [ ] I am running the latest code. Development is very rapid so there are no tagged versions as of now.
- [ ✅] I carefully followed the [README.md](https://github.com/abetlen/llama-cpp-python/blob/main/README.md).
- [ ✅] I [searched using keywords relevant to my issue](https://docs.github.com/en/issues/tracking-your-work-with-issues/filtering-and-searching-issues-and-pull-requests) to make sure that I am creating a new issue that is not already open (or closed).
- [ ✅] I reviewed the [Discussions](https://github.com/abetlen/llama-cpp-python/discussions), and have a new bug or useful enhancement to share.

# Expected Behavior
MiniCPM-V 2.6 memory leak ?

# Current Behavior
I am testing [minicpm-v-2.6](https://huggingface.co/openbmb/MiniCPM-V-2_6-gguf) ,here is part of my test code:

when i run code ,it adds 10MB per inference,i use memory_profiler find in https://github.com/abetlen/llama-cpp-python/blob/2bc1d97c9672320828e70dc8293d5f8754682109/llama_cpp/llama_chat_format.py#L2839


I thought at first that this variable "embed" wasn't being released,I added the code manual release on line 2856,but the program reported an error.
then I replace "embed" with "self._last_image_embed",Memory leaks continue to occur.
# Environment and Context

Please provide detailed information about your computer setup. This is important in case the issue is not reproducible except for under certain specific conditions.then

Example environment info:
```

Python 3.10.10
ubuntu 18.04
cudatoolkit 12.1
llama-cpp-python 0.2.90

```