Improve the skin fix code

- Spoof 404 instead of keeping original URL.
- Move JsonParseException to the package.
- Pass proxy as null to reduce code duplication.

Signed-off-by: TheKodeToad <TheKodeToad@proton.me>

libraries/launcher/org/prismlauncher/fix/skins/SkinFix.java

@@ -41,8 +41,8 @@ import java.net.URLStreamHandlerFactory;
 
 import org.prismlauncher.fix.Fix;
 import org.prismlauncher.utils.Parameters;
-import org.prismlauncher.utils.UrlUtils;
 import org.prismlauncher.utils.logging.Log;
+import org.prismlauncher.utils.url.UrlUtils;
 
 /**
  * Fixes skins by redirecting to other URLs.