Raise error if ClassLabel names is not python list
_The documentation is not available anymore as the PR was closed or merged._ Thanks for your proposed fix, @freddyheppell.

Currently the CI fails because in a test we pass a `tuple` instead of a `list`. I would say we should accept `tuple` as a valid input type as well...

What about checking for `Sequence` instead? Fixed that @albertvillanova, can you approve CI again please? Had some issues related to Pytorch .so files when running tests on my M1 mac, so wasn't able to test locally first. Have got them working on my desktop now though.
Checks type of names provided to ClassLabel to avoid easy and hard to debug errors (closes #5332 - see for discussion)