Add read-only lun field (Azure#21220)

Co-authored-by: Harshitha Akkaraju <hakkaraj@microsoft.com>

Author: harshitha-akkaraju

eng/mgmt/mgmtmetadata/storagepool_resource-manager.txt

@@ -4,11 +4,11 @@ Commencing code generation
 Generating CSharp code
 Executing AutoRest command
 cmd.exe /c autorest.cmd https://github.com/Azure/azure-rest-api-specs/blob/master/specification/storagepool/resource-manager/readme.md --csharp --version=V2 --reflect-api-versions --csharp-sdks-folder=C:\Users\hakkaraj\Workspace\azure-sdk-for-net\sdk
-2021-05-12 23:03:50 UTC
+2021-05-20 04:45:30 UTC
 Azure-rest-api-specs repository information
 GitHub fork: Azure
 Branch:      master
-Commit:      fd3a9d30aa016f2df2d9429590573d48f522f2e9
+Commit:      4b3d05177ad63685fbbb69f147ab104b85ecd7f4
 AutoRest information
 Requested version: V2
 Bootstrapper version:    autorest@2.0.4413