chore: GenAI Client(evals) - corrected the import path for UnifiedMetric from genai_types to types

PiperOrigin-RevId: 893154563

Author: jsondai

vertexai/_genai/_evals_common.py

@@ -1414,7 +1414,7 @@ def _resolve_evaluation_run_metrics(
                     resolved_metrics_list.append(
                         types.EvaluationRunMetric(
                             metric=resolved_metric.name,
-                            metric_config=genai_types.UnifiedMetric(
+                            metric_config=types.UnifiedMetric(
                                 predefined_metric_spec=genai_types.PredefinedMetricSpec(
                                     metric_spec_name=resolved_metric.name,
                                 )
@@ -1455,7 +1455,7 @@ def _resolve_evaluation_run_metrics(
                         resolved_metrics_list.append(
                             types.EvaluationRunMetric(
                                 metric=resolved_metric.name,
-                                metric_config=genai_types.UnifiedMetric(
+                                metric_config=types.UnifiedMetric(
                                     predefined_metric_spec=genai_types.PredefinedMetricSpec(
                                         metric_spec_name=resolved_metric.name,
                                     )