mgmt, loadtest, update tspconfig (#36637)

Author: weidongxu-microsoft

specification/loadtestservice/LoadTestService.Management/tspconfig.yaml

@@ -44,6 +44,8 @@ options:
     namespace: "com.azure.resourcemanager.loadtesting"
     flavor: azure
     service-name: Load Test
+    property-include-always:
+      - "EncryptionPropertiesIdentity.resourceId"
   "@azure-tools/typespec-go":
     service-dir: "sdk/resourcemanager/loadtesting"
     package-dir: "armloadtesting"