Delete empty source folder when deleting all downloads for a manga

It previously only attempted this after deleting a list of chapters, so it wasn't applicable
when deleting from Library or after unfavoriting an entry.

Closes #8594

app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadManager.kt

@@ -239,20 +239,33 @@ class DownloadManager(
 
                 // Delete manga directory if empty
                 if (mangaDir?.listFiles()?.isEmpty() == true) {
-                    mangaDir.delete()
-                    cache.removeManga(manga)
-
-                    // Delete source directory if empty
-                    val sourceDir = provider.findSourceDir(source)
-                    if (sourceDir?.listFiles()?.isEmpty() == true) {
-                        sourceDir.delete()
-                        cache.removeSource(source)
-                    }
+                    deleteManga(manga, source)
                 }
             }
         }
     }
 
+    /**
+     * Deletes the directory of a downloaded manga.
+     *
+     * @param manga the manga to delete.
+     * @param source the source of the manga.
+     */
+    fun deleteManga(manga: Manga, source: Source) {
+        launchIO {
+            downloader.queue.remove(manga)
+            provider.findMangaDir(manga.title, source)?.delete()
+            cache.removeManga(manga)
+
+            // Delete source directory if empty
+            val sourceDir = provider.findSourceDir(source)
+            if (sourceDir?.listFiles()?.isEmpty() == true) {
+                sourceDir.delete()
+                cache.removeSource(source)
+            }
+        }
+    }
+
     private fun removeFromDownloadQueue(chapters: List<Chapter>) {
         val wasRunning = downloader.isRunning
         if (wasRunning) {
@@ -271,20 +284,6 @@ class DownloadManager(
         }
     }
 
-    /**
-     * Deletes the directory of a downloaded manga.
-     *
-     * @param manga the manga to delete.
-     * @param source the source of the manga.
-     */
-    fun deleteManga(manga: Manga, source: Source) {
-        launchIO {
-            downloader.queue.remove(manga)
-            provider.findMangaDir(manga.title, source)?.delete()
-            cache.removeManga(manga)
-        }
-    }
-
     /**
      * Adds a list of chapters to be deleted later.
      *