Failed to create application insights analytics item when type is folder

After tested, api failed to create application insights analytics item and threw below error message when type is folder. According by the error message, it seems that api doesn't support folder type, right?

Http request:
```
PUT https://management.azure.com/subscriptions/xx-xx-xx-xx/resourceGroups/appinsight-itemrg-test01/providers/microsoft.insights/components/appinsights-test01/analyticsItems/item

{
"Id": "",
"Name": "folderexample",
"Content": "folderexample",
"Scope": "shared",
"Type": "folder"
}
```

Error message:
```
insights.AnalyticsItemsClient#Put: Failure responding to request: StatusCode=400 -- Original Error: autorest/azure: Service returned an error. Status=400 Code="BadRequest" Message="Unsupported type parameter" InnerError={"diagnosticcontext":"xx-xx-xx-xx","time":"xxx"}
```

Start by reviewing the Microsoft.Insights analyticsItems PUT operation represented by the request URL and compare its accepted Type values with the reported folder payload and 400 error. Confirm whether folder is supported by the service; done means the REST specification and issue guidance accurately reflect the supported behavior.

Written by the indexing model from the issue text.