Fix crash when open history

app/src/main/java/com/hippo/ehviewer/ui/scene/HistoryScene.kt

@@ -403,7 +403,7 @@ class HistoryScene : BaseToolbarScene() {
         override fun onBindViewHolder(holder: HistoryHolder, position: Int) {
             val gi: GalleryInfo? = getItem(position)
             gi ?: return
-            holder.thumb.load(EhCacheKeyFactory.getThumbKey(gi.gid), gi.thumb!!)
+            gi.thumb?.let { holder.thumb.load(EhCacheKeyFactory.getThumbKey(gi.gid), it) }
             holder.title.text = EhUtils.getSuitableTitle(gi)
             holder.uploader.text = gi.uploader
             holder.rating.rating = gi.rating