Nested Folders: More API fixes (#59316)

* Nested Folder: Fix create, use camel case for JSON properties

* Fix get parents if the folder does not exist

* Add store test for get parents

pkg/services/folder/folderimpl/sqlstore.go

@@ -201,6 +201,13 @@ func (ss *sqlStore) GetParents(ctx context.Context, q folder.GetParentsQuery) ([
 		}
 		return nil, err
 	}
+
+	if len(folders) < 1 {
+		// the query is expected to return at least the same folder
+		// if it's empty it means that the folder does not exist
+		return nil, folder.ErrFolderNotFound
+	}
+
 	return util.Reverse(folders[1:]), nil
 }