Lesson UX improvements for multiple attemps

This issue only needs to be tested in 1 device. Login in mobile master as a student and go to  MM Dev Testing > Lessons > MOBILE-2817 online. Start the lesson. In the first page, put "-1" as the answer and submit. Check that the new page displays the feedback "Sorry, -1 is wrong!" and that you only see 1 button to try again. Click the try again button and now enter a value different than -1 and 10. Check that the new page displays the feedback "Sorry, try again." and that you now see 2 buttons. Click the button "No, I want to go to the next question". Check that you reach a page saying that you'll have to start again from the start. Click the "End lesson" button to finish the lesson and go back to the entry page. Start the lesson again. In the first page, put 10 as the answer and submit. Check that you're sent to the next question. In the next question, answer anything different than "Cardona". Check that the new page displays the feedback "Sorry, that's a wrong answer." and that you see 2 buttons. Click the button "No, I want to go to the next question". Check that you reach a page saying that you'll have to start again from the start. Click the "End lesson" button to finish the lesson and go back to the entry page. Start the lesson again. In the first page, put 10 as the answer and submit. Check that you're sent to the next question. In the new page, enter "Cardona" and submit. Check that you reach a page saying that it's the good ending. Now open the lesson " MOBILE-2817 offline" in the same section. Using the top-right menu, download the lesson. Go offline and repeat the steps 2-14. Everytime you reach the end of lesson and go back to the entry page you'll have to go online, synchronize and then go offline again.