[tracing][bugfix] Use eval run name instead of root span name (#2590)

# Description

For eval line run(s), use run name, instead of root span name.

# All Promptflow Contribution checklist:
- [x] **The pull request does not introduce [breaking changes].**
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significant changes.**
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## General Guidelines and Best Practices
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### Testing Guidelines
- [ ] Pull request includes test coverage for the included changes.

src/promptflow-devkit/promptflow/_sdk/entities/_trace.py

@@ -457,10 +457,7 @@ def _append_evaluations(self, evaluations: typing.List["LineRun"]) -> None:
         for evaluation in evaluations:
             if self.evaluations is None:
                 self.evaluations = dict()
-            # # TODO: 3050320 - make evaluation name equal to batch run name
-            # #       need to update this once UX update their logic
-            # eval_name = evaluation.run if evaluation.run is not None else evaluation.name
-            eval_name = evaluation.name
+            eval_name = evaluation.run if evaluation.run is not None else evaluation.name
             self.evaluations[eval_name] = evaluation
 
     def _to_rest_object(self) -> typing.Dict: