docs: fix the `ImportError` in `google_speech_to_text.ipynb` (#26522)
fix #26370
- #26370
`GoogleSpeechToTextLoader` is a deprecated method in
`langchain_community.document_loaders.google_speech_to_text`.
The new recommended usage is to use `SpeechToTextLoader` from
`langchain_google_community`.
When importing from `langchain_google_community`, use the name
`SpeechToTextLoader` instead of the old `GoogleSpeechToTextLoader`.

Co-authored-by: Erick Friis <erick@langchain.dev>