enable new csharp mpg emitter for informatica (#37806)

Author: live1206

specification/informatica/Informatica.DataManagement.Management/client.tsp

@@ -98,4 +98,9 @@ namespace Informatica.DataManagement {
   );
 
   @@usage(ServerlessRuntimeNetworkProfileUpdate, Usage.output);
+
+  @@alternateType(Azure.ResourceManager.CommonTypes.Resource.id,
+    Azure.Core.armResourceIdentifier,
+    "csharp"
+  );
 }

specification/informatica/Informatica.DataManagement.Management/tspconfig.yaml

@@ -22,10 +22,7 @@ options:
     namespace: "com.azure.resourcemanager.informaticadatamanagement"
     flavor: "azure"
     service-name: "Informatica DataManagement"
-  "@azure-tools/typespec-csharp":
-    flavor: azure
-    clear-output-folder: true
-    model-namespace: true
+  "@azure-typespec/http-client-csharp-mgmt":
     namespace: "Azure.ResourceManager.InformaticaDataManagement"
     emitter-output-dir: "{output-dir}/{service-dir}/{namespace}"
   "@azure-tools/typespec-ts":