fix: remove unnecessary header X_TEST (#5451)

Author: alexander-akait

Diff for: lib/Server.js

@@ -3088,8 +3088,6 @@ class Server {
        */
       const allHeaders = [];
 
-      allHeaders.push({ key: "X_TEST", value: "TEST" });
-
       if (!Array.isArray(headers)) {
         // eslint-disable-next-line guard-for-in
         for (const name in headers) {