[sharing-ng] status code for multiple mount and unmount share

[S-Panta]

Describe the bug

Mounting the share multiple times results in 400 status code. BUt this request isn't a bad request but conflict in request and thus should be 409. As RFC states in https://datatracker.ietf.org/doc/html/rfc7231#section-6.5.8

The 409 (Conflict) status code indicates that the request could not
   be completed due to a conflict with the current state of the target
   resource.  

Same goes for unmounting share multiple times. At the moment, oCIS returns 424 failed dependency status code. MDN docs writes

The HTTP 424 Failed Dependency client error response code indicates that the method could not be performed on the resource because the requested action depended on another action, and that action failed.

What are the appropriate status code for these two request?

Steps to reproduce

1.Login to ocis as admin 2.create a folder test and share to einstein 3. click disable sync. 4. Send API request to mount resource. 5. send the request again to mount resource

curl -X POST 'https://host.docker.internal:9200/graph/v1beta1/drives/{share-Space-Id}/root/children'  
-d '{
    "remoteItem": {
        "id":"'item-id"
    }
}' -ueinstein:relativity