Improve USPS rates by not returning duplicate services (that have the…

… same price, just different description)

src/carriers/USPS.php

@@ -196,19 +196,29 @@ public function getRates(Shipment $shipment): ?RateResponse
         });
 
         $rates = [];
+        $processedRates = [];
 
         foreach (Arr::get($data, 'rateOptions', []) as $shippingRate) {
             $serviceCode = Arr::get($shippingRate, 'rates.0.mailClass', '');
             $serviceName = Arr::get($shippingRate, 'rates.0.description', '');
             $rate = Arr::get($shippingRate, 'rates.0.price', 0);
 
+            // We get duplicate rates (the same `price` and `mailClass`) but different description. Skip them.
+            $rateKey = $rate . '_' . $serviceCode;
+
+            if (isset($processedRates[$rateKey])) {
+                continue;
+            }
+
             $rates[] = new Rate([
                 'carrier' => $this,
                 'response' => $shippingRate,
                 'serviceName' => $serviceName,
                 'serviceCode' => $serviceCode,
                 'rate' => $rate,
             ]);
+
+            $processedRates[$rateKey] = true;
         }
 
         return new RateResponse([