LibAudio: Make FlacLoaderPlugin destructor virtual

Author: https://github.com/LucasChollet
Commit: 27539440df
Pull-request: https://github.com/SerenityOS/serenity/pull/15466
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Userland/Libraries/LibAudio/FlacLoader.h

@@ -49,9 +49,7 @@ class FlacLoaderPlugin : public LoaderPlugin {
 public:
     explicit FlacLoaderPlugin(StringView path);
     explicit FlacLoaderPlugin(Bytes buffer);
-    ~FlacLoaderPlugin()
-    {
-    }
+    virtual ~FlacLoaderPlugin() override = default;
 
     virtual MaybeLoaderError initialize() override;