Fix failing tests on HEAD

I'm working on making https://www.drupal.org/project/acquia_migrate → work on Drupal 10.2.

It took me hours to track down a regression that turns out to have been caused by 📌 Manually clear cache keys from plugin managers with finite variations instead of using cache tags Fixed , because there were no BC layers or deprecations in place.

Then I wanted to create a merge request since Migrate Plus 6.0.1 is still affected by this. But in HEAD, it's already fixed:

    \Drupal::service('plugin.manager.migration')->clearCachedDefinitions();

was added by this MR!

Any chance you can tag a new release? 😊🙏

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