Add service-group entry to service_name.json

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: meghanagupta95

src/service_name.json

@@ -554,6 +554,11 @@
     "AzureServiceName": "Sentinel",
     "URL": "https://learn.microsoft.com/azure/sentinel/overview"
   },
+  {
+    "Command": "az service-group",
+    "AzureServiceName": "Service Groups",
+    "URL": ""
+  },
   {
     "Command": "az sig",
     "AzureServiceName": "Virtual Machines",