docs: api documentation for agents/eval/scoring/datasets (#1400)

# What does this PR do?

- add some docs to OpenAPI for agents/eval/scoring/datasetio

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
- read

[//]: # (## Documentation)

llama_stack/apis/scoring/scoring.py

@@ -17,6 +17,13 @@ ScoringResultRow = Dict[str, Any]
 
 @json_schema_type
 class ScoringResult(BaseModel):
+    """
+    A scoring result for a single row.
+
+    :param score_rows: The scoring result for each row. Each row is a map of column name to value.
+    :param aggregated_results: Map of metric name to aggregated value
+    """
+
     score_rows: List[ScoringResultRow]
     # aggregated metrics to value
     aggregated_results: Dict[str, Any]
@@ -30,6 +37,12 @@ class ScoreBatchResponse(BaseModel):
 
 @json_schema_type
 class ScoreResponse(BaseModel):
+    """
+    The response from scoring.
+
+    :param results: A map of scoring function name to ScoringResult.
+    """
+
     # each key in the dict is a scoring function name
     results: Dict[str, ScoringResult]
 
@@ -55,4 +68,11 @@ class Scoring(Protocol):
         self,
         input_rows: List[Dict[str, Any]],
         scoring_functions: Dict[str, Optional[ScoringFnParams]],
-    ) -> ScoreResponse: ...
+    ) -> ScoreResponse:
+        """Score a list of rows.
+
+        :param input_rows: The rows to score.
+        :param scoring_functions: The scoring functions to use for the scoring.
+        :return: ScoreResponse object containing rows and aggregated results
+        """
+        ...