remove all references of BoardService

spec/javascripts/boards/mock_data.js

-import BoardService from '~/boards/services/board_service';
 import boardsStore from '~/boards/stores/boards_store';
 
 export const setMockEndpoints = (opts = {}) => {
@@ -87,22 +86,6 @@ export const boardsMockInterceptor = config => {
   return [200, body];
 };
 
-export const mockBoardService = (opts = {}) => {
-  const boardsEndpoint = opts.boardsEndpoint || '/test/issue-boards/-/boards.json';
-  const listsEndpoint = opts.listsEndpoint || '/test/-/boards/1/lists';
-  const bulkUpdatePath = opts.bulkUpdatePath || '';
-  const boardId = opts.boardId || '1';
-
-  boardsStore.setEndpoints({
-    boardsEndpoint,
-    listsEndpoint,
-    bulkUpdatePath,
-    boardId,
-  });
-
-  return new BoardService();
-};
-
 export const mockAssigneesList = [
   {
     id: 2,