message: fix duplicate Test which was asserting _id property of an Id
diff: @@ -189,7 +189,7 @@ describe('Duplicate', async () => {
  getResponse.status.should.be.equal(200);
  const courseJson: ICourse = getResponse.body;
  courseJson.active.should.be.equal(false);
  - courseJson.courseAdmin._id.should.be.equal(extractSingleMongoId(teacher));
  + courseJson.courseAdmin.should.be.equal(extractSingleMongoId(teacher));
  courseJson.name.startsWith(course.name).should.be.equal(true);
  courseJson.description.should.be.equal(course.description);
  courseJson.lectures.should.be.instanceOf(Array).and.have.lengthOf(course.lectures.length);
  