http2: fix kUpdateTimer timer refresh

Fixes an oversight from
93eb68e

Wasn't caught by a test.

PR-URL: #18062
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/http2/core.js

@@ -1478,7 +1478,7 @@ class Http2Stream extends Duplex {
     if (this.destroyed)
       return;
     if (this[kTimeout])
-      _unrefActive([kTimeout]);
+      _unrefActive(this[kTimeout]);
     if (this[kSession])
       this[kSession][kUpdateTimer]();
   }