add unset method

src/Potter/Http/Server/HttpServerAwareTrait.php

@@ -25,6 +25,11 @@ trait HttpServerAwareTrait
         return $this->set(self::HTTP_SERVER, $httpServer);
     }
     
+    final protected function unsetHttpServer(): null
+    {
+        return $this->unset(self::HTTP_SERVER);
+    }
+    
     final public function withHttpServer(HttpServer $httpServer): static
     {
         return $this->with(self::HTTP_SERVER, $httpServer);