Clean up LibraryUpdateService a bit

app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateService.kt

@@ -253,48 +253,35 @@ class LibraryUpdateService(
         val failedUpdates = mutableListOf<Pair<Manga, String?>>()
         var hasDownloads = false
 
-        mangaToUpdate
-            .map { manga ->
+        mangaToUpdate.forEach { manga ->
             if (updateJob?.isActive != true) {
                 return
             }
 
-                // Notify manga that will update.
             notifier.showProgressNotification(manga, progressCount.andIncrement, mangaToUpdate.size)
 
-                // Update the chapters of the manga
             try {
-                    val newChapters = updateManga(manga).first
-                    Pair(manga, newChapters)
-                } catch (e: Throwable) {
-                    // If there's any error, return empty update and continue.
-                    val errorMessage = if (e is NoChaptersException) {
-                        getString(R.string.no_chapters_error)
-                    } else {
-                        e.message
-                    }
-                    failedUpdates.add(Pair(manga, errorMessage))
-                    Pair(manga, emptyList())
-                }
-            }
-            // Filter out mangas without new chapters (or failed).
-            .filter { (_, newChapters) -> newChapters.isNotEmpty() }
-            .forEach { (manga, newChapters) ->
+                val (newChapters, _) = updateManga(manga)
+
+                if (newChapters.isNotEmpty()) {
                     if (manga.shouldDownloadNewChapters(db, preferences)) {
                         downloadChapters(manga, newChapters)
                         hasDownloads = true
                     }
 
-                // Convert to the manga that contains new chapters.
-                newUpdates.add(
-                    Pair(
-                        manga,
-                        newChapters.sortedByDescending { ch -> ch.source_order }.toTypedArray()
-                    )
-                )
+                    // Convert to the manga that contains new chapters
+                    newUpdates.add(manga to newChapters.sortedByDescending { ch -> ch.source_order }.toTypedArray())
+                }
+            } catch (e: Throwable) {
+                val errorMessage = if (e is NoChaptersException) {
+                    getString(R.string.no_chapters_error)
+                } else {
+                    e.message
+                }
+                failedUpdates.add(manga to errorMessage)
+            }
         }
 
-        // Notify result of the overall update.
         notifier.cancelProgressNotification()
 
         if (newUpdates.isNotEmpty()) {