Fix "Back Button Works Only on First Form When Multiple Forms Exist"

[timlg07]

Closes #94

[Toflar]

Hey, sorry for being late to the party. I was busy not being close to any computer 😉

Logic looks good to me but I think we don't need the BC handling for mp_form_pageswitch to be honest. This form field name shouldn't be added manually anywhere and if it was, I don't see why this would be API.

So I guess I'd just add a FormManager::getPageSwitchFormFieldName() and use this everywhere. What do you think?

[timlg07]

I completely agree.
But I didn't want to break anything, and since I wasn't able to run the tests locally when I tried it, I didn't want to change them.

I now implemented your suggestion using the additional FormManager method, removed the BC for the tests, and changed them. Can you verify that the tests still work?

[timlg07]

Thanks for the review! I implemented your suggestions :)

[Toflar]

Thank you @timlg07! ❤️