Re-enable PHP Unit Tests for PHP 8.1 and 8.2

[kmanijak]

PHP Unit Tests jobs were failing on every PR. This is most likely due the official WordPress docker images being recently updated (e.g. WordPress 8.2 image) and are now based on debian:12-slim.

That change affected multiple repositories, Gutenberg included. The WordPress/gutenberg#51513 was provided to the @wordpress/env package that unblocks the pipelines for Gutenberg's trunk, but the change is not released yet, hence we cannot update wp-env and have no control over docker-image to apply the changes manually.

To unblock PRs and making pipeline passing the PHP Unit Tests for PHP 8.1 and 8.2 were disabled: #9859. Tests for 7.4 and 8.0 are still running.

The scope of this issue is to:

• keep an eye on wp-env releases (check this issue, potentially the out-of-schedule patch release will happen: wp-env: try to fix failing PHP Github actions WordPress/gutenberg#51513)
• once the PHP Unit Tests could run properly, readable them by reverting Temporarily skip PHP Unit Tests for PHP 8.1 and 8.2 #9859

[noahtallen]

You should be able to re-enable this again! I updated wp-env to v8.1.1 on npm today, which includes the fix.