[Groudnedness] Handle strings and single entries

[ahibrahimm]

Description

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[Copilot]

Pull Request Overview

This pull request adds functionality to handle string inputs and single-entry lists in the GroundednessEvaluator. The changes improve input validation by extracting context validation logic into a separate method and adding checks for single-entry inputs.

Key Changes:

• Extracted context validation logic into a reusable _validate_context method
• Added _is_single_entry helper method to detect single-entry inputs (strings or single-item lists)
• Implemented validation to raise NOT_APPLICABLE error when no context is available for single-entry query/response pairs
• Modified response filtering to conditionally call _filter_file_search_results only when context is valid

[Copilot]

There's a potential type mismatch bug in this conditional logic. The _filter_file_search_results method expects a List[Dict[str, Any]] parameter, but response could be a string.

Looking at the code flow:

1. Line 304 gets response from kwargs, which could be a string (per the first __call__ overload)
2. This code path is only executed when context or conversation is NOT provided (line 301-302)
3. If _validate_context(context) returns True, it calls _filter_file_search_results(response)
4. However, _filter_file_search_results at line 332 expects messages: List[Dict[str, Any]]

If response is a string and _validate_context(context) is True, this will cause a runtime error when _filter_file_search_results tries to iterate over the string and call .get() on characters.

Consider adding a type check before calling _filter_file_search_results or ensuring that this code path is only reached when response is guaranteed to be a list.

Suggested change

	filtered_response = self._filter_file_search_results(response) if self._validate_context(context) else response
	if self._validate_context(context) and isinstance(response, list):
	filtered_response = self._filter_file_search_results(response)
	else:
	filtered_response = response