Feature Request: Add GLM 4.6 support

[Geechan]

Prerequisites

• I am running the latest code. Mention the version if possible as well.
• I carefully followed the README.md.
• I searched using keywords relevant to my issue to make sure that I am creating a new issue that is not already open (or closed).
• I reviewed the Discussions, and have a new and useful enhancement to share.

Feature Description

GLM 4.6 marks the layer.nextn.shared_head_head and layer.nextn.embed_tokens tensors as not required, which prevents the model from loading with the error llama_model_load: error loading model: missing tensor 'blk.92.nextn.embed_tokens.weight'.

Motivation

Adds GLM 4.6 support and allows it to load.

Possible Implementation

A simple change to the code is needed to mark the tensors as not required, allowing the model to load. See here:
ggml-org/llama.cpp#16359