UI loading improvements

Fixed: Caching for dynamically loaded JS files
Fixed: Incorrect caching of initialize.js
(cherry picked from commit f0cb5b81f140c67fa84162e094cc4e0f3476f5da)

src/Prowlarr.Http/Middleware/CacheableSpecification.cs

@@ -46,7 +46,7 @@ namespace Prowlarr.Http.Middleware
                 return false;
             }
 
-            if (path.EndsWith("/initialize.js"))
+            if (path.EndsWith("/initialize.json"))
             {
                 return false;
             }