[Feature Request]: Softer redirection for learners who need to revisit earlier cards in a lesson

[seanlip]

Is your feature request related to a problem? Please describe.

Currently, learners who play lessons are sometimes redirected to an earlier card in the lesson if they get an answer wrong, because they haven't properly learned the necessary skill for it. However, the way this is currently done involves learners getting routed back to that earlier card, and then having to re-answer all the intermediate questions before they get back to the card they were originally at. This feels like a punishment and causes frustration for learners.

Describe the solution you'd like

When a learner is redirected, rather than putting a new instance of the earlier card on the "card stack", we should have the following behaviour instead:

• Do not add a new card to the stack.
• Instead, show the feedback message, and when they click the "learn again" button, take them back in their exploration history to the most recent time they encountered that card. This should be equivalent to them pressing the "back button" multiple times.
• To get to where they left off, they can then press the "forward button" multiple times to end up where they left off, and re-attempt the question. (This is different from the old behaviour where they would need to re-attempt all the questions in between as well.)

For reference, this behaviour was implemented in Web in this issue and corresponding PR.

Describe alternatives you've considered

We have a design project open for handling the general case where learners get stuck while playing a lesson. However, this is taking some time to complete, so this issue suggests a more "quick-and-dirty" solution that mimics the approach currently taken on Web.

Additional context

You can create the following test exploration to reproduce this issue:

1. Create an exploration that includes, in one of its later cards: a wrong answer, feedback, and a loop-back to an earlier card.
2. As a learner, play the exploration and enter the wrong answer in the later card. View the feedback and click the blue "Learn Again" button.
3. Observe that you are looped back to the earlier card, and that you would need to go through all the intermediate cards manually again. (Instead, after clicking "Learn Again", the learner should be navigated back to the earlier card instead, so that they can navigate to the last card later by clicking the forward arrow rather than re-entering all the answers again.)