Fix: handle deprecated 'embedding' kwarg with warning

[lxcxjxhx]

Fixes #2210

Problem

When users create a model with \Llama(embedding=True), the \embedding\ parameter is silently discarded by **kwargs, causing a \RuntimeError\ when calling \embed()\ method later.

Solution

• Renamed the parameter from \embedding\ to \embeddings\ (plural form) to match \self.context_params.embeddings\
• Added backward compatibility: if users still use the old \embedding\ parameter, a \DeprecationWarning\ is issued and the value is automatically assigned to \embeddings\

Testing

Verified that:

1. \Llama(embeddings=True)\ works correctly
2. \Llama(embedding=True)\ still works but shows a deprecation warning
3. The \embed()\ method can be called successfully in both cases