Do not mark `MetaboxOrchestra\BoxInfo` as final

[widoz]

Does make sense since the class does not implements the following methods by an interface that the class isn't marked as final.

• id
• title
• context
• priority

I understand that's just a data structure but in terms of unit tests correctness I want to mock the instance of that class but obviously it's not possible.

Additional reasons are:

• The constructor make calls to Wp functions which is something I would not do in an unit test
• I cannot make expectations for the instance and I have to construct more instances within the same test if I want to make smaller different tests.
• A class should not be marked as final if there are methods which are not part of an interface. That's just an opinionable idea but like any other reason to mark a class final .