1c0f08fc5b
* update cover logic when thumbnail url becomes null
* always clear cover on refresh even if custom cover is set
* remove concurrency changes
(cherry picked from commit 5723c184b1)
# Conflicts:
# app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateService.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryController.kt