Drupal 10 compatibility fixes

Fixed using PHPStan and the "upgrade_status" module.

Tested installing the module on Drupal 10 after the changes.

Interesting, upgrade_status forgot to mention the test module! Fixed, please review.

Thanks @Grevil!

I think all .info.yml files should have an equal core_version_requirement.
If that's not possible, we should perhaps increase the values for all?

I think it is fine in this case, as the only info file that differentiates, is for the test module.

Let's remove the core_version_requirement as of #3096609: Allow contrib test modules to not need a core or core_version_requirement key →

Merged!

Automatically closed - issue fixed for 2 weeks with no activity.