Cache issues with lesson ordering

[renatho]

Steps to Reproduce

1. Create an atomic site (I tested on Pressable).
2. Create a course with modules and lessons.
3. Save it.
4. Change the lessons order.
5. Save it, and refresh the editor.

What I Expected

To see the lessons in the saved order.

What Happened Instead

The previous order is displayed.

The same issue happens if we sort the lessons through Sensei LMS > Lessons > Order Lessons, and check the order in the frontend (the order in the frontend will be cached).

PHP / WordPress / Sensei LMS version

PHP 8.1 / WordPress 6.3.1 / Sensei LMS 4.16.1

Browser / OS version

Chrome

Screenshot / Video

Screen.Recording.2023-09-01.at.11.50.12.mov

Context / Source

A while ago, I worked on #4236, fixing a related thing. The cause here is the same cache, but in different parts of the code. Since it's been a while, I don't remember exactly the causes in the core, but maybe going deeper into the issue again, we could find a better solution. If not, a short-term solution could be always avoiding the cache in that situation, but I'm not sure about performance complications.

More context:

• p1693520624650459/1692982559.274589-slack-C02P7FHLVR9
• 6700401-zd-a8c (I'm not totally sure if it's the issue for this user)

[github-actions]

Support References

This comment is automatically generated. Please do not edit it.

• 6700401-zen
• 8437141-zen
• 8589276-zen

[donnapep]

Related #6632

[joashrajin]

This user reports that Lesson and Module ordering resets after saving

8437141-zd-a8c

[igotdes]

User in #8437141-zen says they tried the fix above, but it didn't work for them:

[...] I applied the patch to the corresponding file in Sensei, but it still does not work.

[jinnypark]

8589276-zen

I'm trying to change the order of lessons or modules and after I make any edit and press save the order returns to what it was before (the changes are not saved)
We've already upped our max_input_vars in case this was the issue but this doesn't resolve the issue