SecretStr for fireworks api (#12475)
- **Description:** This pull request removes secrets present in raw
format,
- **Issue:** Fireworks api key was exposed when printing out the
langchain object
[#12165](https://github.com/langchain-ai/langchain/issues/12165)
- **Maintainer:** @eyurtsev
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Co-authored-by: Bagatur <baskaryan@gmail.com>
