feat!: Drop import_from_modulestore app (3/3 -- uninstall app) (#37241)

https://github.com/openedx/edx-platform/issues/37242

.github/workflows/unit-test-shards.json

@@ -238,7 +238,6 @@
       "cms/djangoapps/cms_user_tasks/",
       "cms/djangoapps/course_creators/",
       "cms/djangoapps/export_course_metadata/",
-      "cms/djangoapps/import_from_modulestore/",
       "cms/djangoapps/maintenance/",
       "cms/djangoapps/models/",
       "cms/djangoapps/pipeline_js/",