Nested Folders: Some API fixes (#59298)

* Nested Folders: Fix API responses

* Fix panic during deletions

* Add test

pkg/api/dtos/folder.go

@@ -20,10 +20,10 @@ type Folder struct {
 	Created       time.Time              `json:"created"`
 	UpdatedBy     string                 `json:"updatedBy"`
 	Updated       time.Time              `json:"updated"`
-	Version       int                    `json:"version"`
+	Version       int                    `json:"version,omitempty"`
 	AccessControl accesscontrol.Metadata `json:"accessControl,omitempty"`
 	// only used if nested folders are enabled
-	ParentUID string `json:"parentUid"`
+	ParentUID string `json:"parentUid,omitempty"`
 }
 
 type FolderSearchHit struct {

pkg/api/folder.go

@@ -251,6 +251,7 @@ func (hs *HTTPServer) newToFolderDto(c *models.ReqContext, g guardian.DashboardG
 		Updated:       folder.Updated,
 		Version:       folder.Version,
 		AccessControl: hs.getAccessControlMetadata(c, c.OrgID, dashboards.ScopeFoldersPrefix, folder.UID),
+		ParentUID:     folder.ParentUID,
 	}
 }