Fix Menu popup hover flicker

[Coderxrohan]

Fix Menu popup hover flicker

Description

Popup Menu items had a visible hover delay when moving rapidly between items.
This was caused by inherited CSS transitions on .p-menuitem-link, which led
to overlapping hover-in / hover-out animations and resulted in visual glitches.

Solution

Disable transitions specifically for popup Menu items by adding an explicit
rule for .p-menu .p-menuitem-link.

This ensures hover styles are applied immediately, eliminating flicker and
improving UX consistency.

Scope of Change

• CSS-only change
• Scoped strictly to popup Menu (.p-menu)
• No impact on Menubar, MegaMenu, or other navigation components
• No API or behavior changes

Verification

• Reproduced the issue locally using the Menu → Popup demo
• Verified hover behavior by moving quickly between items
• Confirmed via DevTools that transition: none is applied to
  .p-menuitem-link

Fixes #7506 (Menu: Visual glitches in hovering effect)

[Coderxrohan]

This change adds an explicit CSS rule for .p-menu .p-menuitem-link
to disable hover transitions for popup Menu items. Previously, inherited transitions caused overlapping hover-in and hover-out animations when moving quickly between items, resulting in a visible flicker. Removing the transition ensures hover styles are applied immediately, fixing the visual glitch without affecting Menubar, MegaMenu, or any other components.