Datalake: showonly=delete is missing from listBlobHierarchySegment request

It is included in recording.

Looking at the code, the `listBlobHierarchySegment` is only ever used to list deleted paths in `listDeletedPathsSegment` so maybe swagger is written in that way to use the default value of "deleted". Do we want to make similar changes in typespec?

```json
"ListBlobsShowOnly": {
"name": "showonly",
"in": "query",
"required": false,
"type": "string",
"enum": [
"deleted"
],
"x-ms-enum": {
"name": "ListBlobsShowOnly",
"modelAsString": false
},
"x-ms-parameter-location": "method",
"description": "Include this parameter to specify one or more datasets to include in the response."
},
```
I am working around it in convenience layer by passing "deleted" to generated layer.