Update PHPCS rules for Drupal 11.x

Confirmed: latest nightly run fails in the same way: https://git.drupalcode.org/project/experience_builder/-/jobs/3756953

FWIW core excludes Drupal.Commenting.VariableComment.Missing for tests, perhaps we should do the same, but keep it for runtime code as it can be useful to actually document things.

@longwave in #7: I agree it can be useful! But definitely not always.

The majority of the comments that that rule forced us to add were not meaningful; they just restated what the name already said. In core too, more often than not, these comments are actually stale and hence (anywhere between "slightly" and "very") wrong. In XB, I think the combined use of:

• more typed objects
• PHPStan level 8, which then includes array shape definitions

massively reduces the need that once existed. I think that rule made sense in an era before those two things, but not now. The collateral damage is too great.