Add invalidateCacheTags to post_import queueworker

[janette]

Temporary fix for stale cache after post_import

QA Steps

1. Set up vanilla site
2. ddev drush en sample_content
3. ddev drush dkan-sample-content:create
4. ddev drush dkan:datastore:import 3a187a87dc6cd47c48b6b4c4785224b7
5. Confirm datastore results: curl http://dkan.ddev.site/api/1/datastore/query/cedcd327-4e5d-43f9-8eb1-c11850fa7c55/0
6. Confirm endpoint is cached: curl -I http://dkan.ddev.site/api/1/datastore/query/cedcd327-4e5d-43f9-8eb1-c11850fa7c55/0 , look for x-drupal-cache: HIT
7. ddev drush queue:run post_import
8. Confirm endpoint is now not cached: curl -I http://test1.ddev.site/api/1/datastore/query/cedcd327-4e5d-43f9-8eb1-c11850fa7c55/0 , x-drupal-cache should be MISS or simply not present