Clean up download ahead logic

- Remove redundant chapter sorting logic when fetching next chapter(s)
- Remove redundant download queue checks (it'll handle already queued or downloaded items)
- Trigger download ahead when read >= 25% of chapter rather than 20%
- Rely on download cache when checking if next chapter is downloaded to avoid jank (fixes #8328)

(cherry picked from commit fc184f1cfa)

# Conflicts:
#	app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateService.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt

app/src/main/java/eu/kanade/domain/DomainModule.kt

@@ -34,7 +34,7 @@ import eu.kanade.domain.extension.interactor.GetExtensionSources
 import eu.kanade.domain.extension.interactor.GetExtensionsByType
 import eu.kanade.domain.history.interactor.DeleteAllHistory
 import eu.kanade.domain.history.interactor.GetHistory
-import eu.kanade.domain.history.interactor.GetNextChapter
+import eu.kanade.domain.history.interactor.GetNextUnreadChapters
 import eu.kanade.domain.history.interactor.RemoveHistoryById
 import eu.kanade.domain.history.interactor.RemoveHistoryByMangaId
 import eu.kanade.domain.history.interactor.UpsertHistory
@@ -94,7 +94,7 @@ class DomainModule : InjektModule {
         addFactory { GetLibraryManga(get()) }
         addFactory { GetMangaWithChapters(get(), get()) }
         addFactory { GetManga(get()) }
-        addFactory { GetNextChapter(get(), get(), get(), get()) }
+        addFactory { GetNextUnreadChapters(get(), get(), get(), get()) }
         addFactory { ResetViewerFlags(get()) }
         addFactory { SetMangaChapterFlags(get()) }
         addFactory { SetMangaDefaultChapterFlags(get(), get(), get()) }