embedding : show full embedding for single prompt (#6342)

embedding : show full embedding for single prompt (#6342)

* embedding : show full embedding for single prompt

To support the use case of creating an embedding for a given prompt, the entire embedding and not just the first part needed to be printed.

Also, show cosine similarity matrix only if there is more than one prompt, as the cosine similarity matrix for a single prompt is always `1.00`.

* Update examples/embedding/embedding.cpp

---------

Co-authored-by: Georgi Gerganov <redacted>