https: change var to let in lib/https.js

Changed a variable declaration.

PR-URL: #30320
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Author: g-prokofyeva

lib/https.js

@@ -162,7 +162,7 @@ Object.setPrototypeOf(Agent, HttpAgent);
 Agent.prototype.createConnection = createConnection;
 
 Agent.prototype.getName = function getName(options) {
-  var name = HttpAgent.prototype.getName.call(this, options);
+  let name = HttpAgent.prototype.getName.call(this, options);
 
   name += ':';
   if (options.ca)