Changing operation name to match other related API for documentation (Azure#24588)

Author: MattEberhart-MSFTE

specification/cost-management/resource-manager/Microsoft.CostManagement/stable/2023-03-01/costmanagement.benefits.json

@@ -656,7 +656,7 @@
         "tags": [
           "BenefitUtilizationSummariesAsync"
         ],
-        "operationId": "GenerateBenefitUtilizationSummariesReportAsync_GenerateBySavingsPlanId",
+        "operationId": "GenerateBenefitUtilizationSummariesReport_GenerateBySavingsPlanId",
         "description": "Triggers generation of a benefit utilization summaries report for the provided savings plan.",
         "externalDocs": {
           "url": "https://docs.microsoft.com/rest/api/cost-management/"