Drop `@skipIf(cms_version)` conditions — CMS <4.1 tests removed from CI

[mrbazzan]

Remove all decorators in the tests/ folder that skips some part of the
test suite. These conditions are for tests less than cms4.1 which have all
been removed from the CI

Tip: Run grep -Hib 'skip' tests/* from the root djangocms-snippet directory

[dnlzrgz]

I think I can handle this!