Add support for embedding model tuning.

[palindsay]

https://unsloth.ai/docs/new/embedding-finetuning

[ARahim3]

Hi @palindsay, thank you for requesting this.
Yes, this is on my to-do list. I am currently working on STT and TTS fine-tuning, the embedding model fine-tuning support will be added soon.
I'll comment here once I get the embedding model working.