[ReleasePR dashboard] Update service name in desc (#2235)

Create to sync Azure/azure-rest-api-specs#18110
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/dashboard?expand=1)

Author: msftbot[bot]

schemas/2021-09-01-preview/Microsoft.Dashboard.json

@@ -30,7 +30,7 @@
         },
         "name": {
           "type": "string",
-          "description": "The name of Azure Managed Workspace for Grafana."
+          "description": "The name of Azure Managed Grafana."
         },
         "properties": {
           "oneOf": [