Add ManagedServiceIdentityV4 to known management types list. (#53851)

* add ManagedServiceIdentityV4 to known management types list.

* update test project.

Author: haiyuazhang

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Primitives/KnownManagementTypes.cs

@@ -42,6 +42,7 @@ internal class KnownManagementTypes
             ["Azure.ResourceManager.CommonTypes.ExtendedLocation"] = typeof(ExtendedLocation),
             ["Azure.ResourceManager.CommonTypes.ExtendedLocationType"] = typeof(ExtendedLocationType),
             ["Azure.ResourceManager.CommonTypes.ManagedServiceIdentity"] = typeof(ManagedServiceIdentity),
+            ["Azure.ResourceManager.Legacy.ManagedServiceIdentityV4"] = typeof(ManagedServiceIdentity),
             ["Azure.ResourceManager.CommonTypes.ManagedServiceIdentityType"] = typeof(ManagedServiceIdentityType),
             ["Azure.ResourceManager.CommonTypes.OperationStatusResult"] = typeof(OperationStatusResult),
             ["Azure.ResourceManager.CommonTypes.SystemData"] = typeof(SystemData),

eng/packages/http-client-csharp-mgmt/generator/TestProjects/Local/Mgmt-TypeSpec/foo.tsp

@@ -16,6 +16,9 @@ model Foo is TrackedResource<FooProperties, false> {
   ...ResourceNameParameter<Foo, SegmentName = "foos">;
 
   ...ExtendedLocationProperty;
+
+  #suppress "@azure-tools/typespec-azure-core/no-legacy-usage" "Existing usage of legacy type"
+  ...Azure.ResourceManager.Legacy.ManagedServiceIdentityV4Property;
 }
 
 @useSystemTextJsonConverter("csharp")