updated H5P standalone to the latest version (2.1.3)

mc_backend/mcserver/app/services/textService.py

mc_backend/tests.py

mc_frontend/README.md

mc_frontend/package-lock.json

mc_frontend/package.json

mc_frontend/src/app/exercise-list/exercise-list.page.spec.ts

mc_frontend/src/app/exercise-list/exercise-list.page.ts

mc_frontend/src/app/exercise.service.spec.ts

mc_frontend/src/app/exercise.service.ts

mc_frontend/src/app/exercise/exercise.page.html

mc_frontend/src/app/helper.service.ts

mc_frontend/src/app/models/enum.ts

mc_frontend/src/app/models/eventRegistry.ts

mc_frontend/src/app/models/h5p-standalone.class.ts

mc_frontend/src/app/models/h5pEventDispatcherMock.ts

mc_frontend/src/app/models/mockMC.ts

mc_frontend/src/app/preview/preview.page.spec.ts

mc_frontend/src/app/preview/preview.page.ts

mc_frontend/src/app/test/test.page.spec.ts

mc_frontend/src/app/test/test.page.ts