fix: 修复emby组件错误

Author: shoaky009

plugins/common-plugin/src/main/kotlin/io/github/shoaky/sourcedownloader/common/EmbyImageTagger.kt

@@ -27,7 +27,7 @@ object EmbyImageTagger : FileTagger {
             return null
         }
 
-        val image = ImageIO.read(sourceFile.path.toFile())
+        val image = ImageIO.read(sourceFile.path.toFile()) ?: return null
         if (image.width >= image.height) {
             return "thumb"
         }