Support input_embeds in torch exportable decoders (#39836)
* Support input_embeds in torch exportable decoders
* Hybrid cache update
* Manually change some callsites
* AI changes the rest of the call sites
* Make either input_ids/inputs_embeds mandatory
* Clean up
* Ruff check --fix
* Fix test
* pr review
* Revert config/generation_config changes
* Ruff check
