Simplify EhEngine.getPreviewList

app/src/main/kotlin/com/hippo/ehviewer/client/EhEngine.kt

@@ -226,7 +226,7 @@ object EhEngine {
     }
 
     suspend fun getPreviewList(url: String) = ehRequest(url, EhUrl.referer).fetchUsingAsText {
-        GalleryDetailParser.parsePreviewList(this) to GalleryDetailParser.parsePreviewPages(this)
+        GalleryDetailParser.parsePreviewList(this)
     }
 
     suspend fun getFavorites(url: String) = ehRequest(url, EhUrl.referer).fetchUsingAsByteBuffer(FavoritesParser::parse)

app/src/main/kotlin/com/hippo/ehviewer/ui/screen/GalleryPreviewScreen.kt

@@ -95,7 +95,7 @@ fun GalleryPreviewScreen(galleryDetail: GalleryDetail, toNextPageArg: Boolean, n
                         (up..end).filterNot { it in previewPagesMap }.map { it / pgSize }.toSet()
                             .parMap(concurrency = Settings.multiThreadDownload) { page ->
                                 val url = EhUrl.getGalleryDetailUrl(gid, token, page, false)
-                                EhEngine.getPreviewList(url).first.first
+                                EhEngine.getPreviewList(url).first
                             }.flatten().forEach {
                                 previewPagesMap[it.position] = it
                                 if (Settings.preloadThumbAggressively) {