docs: misc academy docs fixes

[artogahr]

Hi folks, I'm going through some of the academy docs, I'll try to fix any inconsistencies I find here

[apify-service-account]

✅ Preview for this PR (commit 4b954313) is ready at https://pr-2536.preview.docs.apify.com (see action run).

[honzajavorek]

Thanks for working on this! omg, the Christmas tree 🤦‍♂️ I remember I browsed IKEA products for a while to find a category which won't have any four digit prices, so that the exercise is simple. And they add a Christmas tree to artificial plants 🔥 👿 🔥

[artogahr]

the amazon frontend seems to have changed it seems, it's not possible to get more than one price for the products with crawlee since they are dynamically loaded. I don't think it's worth refactoring over, I've just added a note to https://docs.apify.com/academy/expert-scraping-with-apify/actors-webhooks

[artogahr]

I'm done with the onboarding, I fixed most things I was able to find, no perfect solutions for anything but still in the spirit of "if it's better than current, ship it" 😄