fix: ragas - pin langchain-community to avoid ModuleNotFoundError

[anakin87]

Related Issues

• No module named 'langchain_community.chat_models.vertexai' vibrantlabsai/ragas#2741 (ragas seems to be not very actively maintained at this point)
• failing tests: https://github.com/deepset-ai/haystack-core-integrations/actions/runs/26377641552/job/77640709997

Proposed Changes:

• pin langchain-community to a version that includes langchain_community.chat_models.vertexai (imported in ragas)

How did you test it?

CI

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	langchain-community@​0.4.2 ⏵ 0.4.1	+29

View full report

[github-actions]

Coverage report (ragas)

This PR does not seem to contain any modification to coverable code.

[sjrl]

Thanks!