Fixed: Use FlareSolverr response body instead of re-requesting

After FlareSolverr solves a Cloudflare challenge, Prowlarr discards the
response body and makes a second HTTP request using only the returned
cookies. This fails because Cloudflare's cf_clearance cookie is bound to
the solver's TLS fingerprint, which .NET's HttpClient cannot replicate.

Use the solved HTML body from FlareSolverr directly when available,
falling back to the cookie-based retry only if no body was returned.

Also fix the error status code reference (response → flaresolverrResponse).

Fixes #2561

src/NzbDrone.Core/IndexerProxies/FlareSolverr/FlareSolverr.cs

@@ -58,7 +58,7 @@ public override HttpResponse PostResponse(HttpResponse response)
 
             if (flaresolverrResponse.StatusCode != HttpStatusCode.OK && flaresolverrResponse.StatusCode != HttpStatusCode.InternalServerError)
             {
-                throw new FlareSolverrException("HTTP StatusCode not 200 or 500. Status is :" + response.StatusCode);
+                throw new FlareSolverrException("HTTP StatusCode not 200 or 500. Status is :" + flaresolverrResponse.StatusCode);
             }
 
             var result = JsonConvert.DeserializeObject<FlareSolverrResponse>(flaresolverrResponse.Content);
@@ -71,7 +71,20 @@ public override HttpResponse PostResponse(HttpResponse response)
 
             InjectCookies(newRequest, result);
 
-            //Request again with User-Agent and Cookies from Flaresolverr
+            // Use FlareSolverr's response body directly — a second HTTP request
+            // gets 403'd because cf_clearance is bound to the solver's TLS fingerprint
+            if (result.Solution.Response.IsNotNullOrWhiteSpace())
+            {
+                return new HttpResponse(
+                    response.Request,
+                    response.Headers,
+                    response.Cookies,
+                    result.Solution.Response,
+                    response.ElapsedTime,
+                    HttpStatusCode.OK);
+            }
+
+            // Fallback: if FlareSolverr returned no body, try cookies (original behavior)
             var finalResponse = _httpClient.Execute(newRequest);
 
             return finalResponse;