chore!: remove unused raise_on_invalid_filter_syntax utility function

[anakin87]

Related Issues

I noticed raise_on_invalid_filter_syntax utility function:

• never used across Haystack ecosystem
• wrong implementation: a possible better implementation can be found in many document stores like Pgvector

Proposed Changes:

• remove it

How did you test it?

CI

Notes for the reviewer

I also considered fixing it and then reusing it across core integrations, but it seemed high effort for low value

Checklist

• I have read the contributors guidelines and the code of conduct.
• I have updated the related issue with new insights and changes.
• I have 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: and added ! in case the PR includes breaking changes.
• I have documented my code.
• I have added a release note file, following the contributors guidelines.
• I have run pre-commit hooks and fixed any issue.

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
haystack-docs	Ignored		Jul 10, 2026 8:46am

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Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
haystack/utils
__init__.py
filters.py
Project Total

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