feat(ollama): add `dimensions` to `OllamaEmbeddings` (#36543)
Fixes #34623
Add `dimensions` field to `OllamaEmbeddings` to allow users to specify
output embedding size for models that support variable dimensions . The
field is passed
directly to the Ollama client's `embed()` call for both sync and async
methods.
**How I verified it works:**
- Ran unit tests: `python -m pytest tests/unit_tests/ -v`
- Ran integration tests against a live Ollama instance:
`OLLAMA_HOST=http://ollama:11434 python -m pytest
tests/integration_tests/ -v`
- Confirmed that passing `dimensions=768` no longer raises
`extra_forbidden`
Pydantic validation error and returns embeddings of the expected size.
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Co-authored-by: Mason Daugherty <mason@langchain.dev>
Co-authored-by: Mason Daugherty <github@mdrxy.com>
