convert : bailingmoe : set yarn metadata if present

[CISC]

Set YaRN metadata if present since support was finally added and it looks to be bog standard. Tested with Ling-Coder-lite (manually configured).

NOTE: For some reason they have not updated the config on any of their models, so you have to add/enable this yourself, can be done in one of the following ways:

• On the commandline (no changes to old GGUFs necessary):

  ./llama-cli -m Ling-Coder-lite.gguf -c 16384 --rope-scaling yarn --rope-scale 4

• Change max_position_embeddings (multiply by 4) and rope_scaling in config.json and reconvert:

  {
      "factor": 4.0,
      "original_max_position_embeddings": 4096,
      "type": "yarn"
  }

• Add/change metadata to old GGUF with gguf_editor_gui.py
• Download dynamically modified GGUF using gguf-editor