Ensure `num_logits_to_keep` is always set to 1 for generate calls (#1681)

* support scalar tensor tolist()

* gemma support num_logits_to_keep

* set num_logits_to_keep in phi3_v and chatterbox too

* set num_logits_to_keep in qwen2_vl and multi_modality

* allow num_logits_to_keep to be used in encoder-decoder models

* Deduplicate set logic