Disable ensure_ascii when dumping to json tool responses

[silvanocerza]

Related Issues

• fixes experimental: OpenAIFunctionCaller string parsing haystack#8170

Proposed Changes:

Set ensure_ascii=False when dumping to JSON tool or function calls, this way special chars like emojis are not lost.

How did you test it?

I tested manually.

Notes for the reviewer

N/A

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:.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 11917903376

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 9 unchanged lines in 4 files lost coverage.
• Overall coverage remained the same at 89.551%

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Files with Coverage Reduction	New Missed Lines	%
components/tools/tool_invoker.py	1	93.67%
components/tools/openai/function_caller.py	2	92.86%
components/generators/chat/openai.py	3	97.16%
components/tools/openapi/openapi_tool.py	3	58.43%

Totals
Change from base Build 11903548008:	0.0%
Covered Lines:	1894
Relevant Lines:	2115

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💛 - Coveralls