fix: 🐛 Never allow sequences (comma operator)

We inherit no-sequences: error from airbnb-base, but by default, that rule still allows sequences if they're wrapped in parentheses. We do not want to allow even that, since the comma operator is not well known/understood, and instances of this are likely mistakes anyway.

This is not marked as a breaking change, since this is considered an oversight of the existing linting configuration.

See gitlab-org/gitlab!68960 (merged) for fixes for this in GitLab.