PanelMenu: Up and down arrow key navigation not working with dropdown items in PanelMenu

[vincyrose1970]

Describe the bug

PanelMenu: Up and down arrow key navigation not working with dropdown items in PanelMenu

The issue is reproducable in the main website itself, so not providing a stackblitz project.
https://primereact.org/panelmenu/#basic

Reproducer

https://primereact.org/panelmenu/#basic

System Information

System:
    OS: Windows 11 10.0.26100
    CPU: (8) x64 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
    Memory: 2.17 GB / 15.41 GB
  Binaries:
    Node: 22.12.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.9.0 - C:\Program Files\nodejs\npm.CMD
    pnpm: 10.15.0 - C:\Users\AkshayAntony\AppData\Roaming\npm\pnpm.CMD
  Browsers:
    Chrome: 141.0.7390.76
    Edge: Chromium (140.0.3485.54)
    Firefox: 143.0 - C:\Program Files\Mozilla Firefox\firefox.exe
    Internet Explorer: 11.0.26100.1882
  npmPackages:
    react: 18.3.1 => 18.3.1

Steps to reproduce the behavior

1. Go to https://primereact.org/panelmenu/#basic
   Click on a menu item with dropdown or arrow key, say 'Files'
   Try to navigate using arrow keys, either UP arrow key or Down arrow key.
   The focus is not pointing to the items in sub menu and navigation is not working.

I checked PrimeNg and PrimeVue and this navigation is working perfectly there but not in PrimeReact.

Expected behavior

The focus should point to the items in sub menu and user should be able to navigate using arrow keys.

@akshayaqburst can you fix this as well, as you fixed a related bug in #8341?