Emit update to clients after adding all mangas to the queue (#521)

Emitting updates before all the mangas were added to the queue could lead to e.g. wrong progress calculation.

server/src/test/kotlin/suwayomi/tachidesk/manga/impl/update/TestUpdater.kt

@@ -13,8 +13,8 @@ class TestUpdater : IUpdater {
     private val _status = MutableStateFlow(UpdateStatus())
     override val status: StateFlow<UpdateStatus> = _status.asStateFlow()
 
-    override fun addMangaToQueue(manga: MangaDataClass) {
-        updateQueue.add(UpdateJob(manga))
+    override fun addMangasToQueue(mangas: List<MangaDataClass>) {
+        mangas.forEach { updateQueue.add(UpdateJob(it)) }
         isRunning = true
         updateStatus()
     }