Fix: Support Gluetun widget auth (#4034)

src/widgets/gluetun/widget.js

@@ -1,8 +1,8 @@
-import genericProxyHandler from "utils/proxy/handlers/generic";
+import credentialedProxyHandler from "utils/proxy/handlers/credentialed";
 
 const widget = {
   api: "{url}/v1/{endpoint}",
-  proxyHandler: genericProxyHandler,
+  proxyHandler: credentialedProxyHandler,
 
   mappings: {
     ip: {