…'s value

The hook overwrote the overlay panel's inline z-index with a hard-coded
constant. That value can sit below the current modal tier, and PrimeReact's
ZIndexUtils.clear() un-registers an overlay by reading its inline z-index
back — overwriting it made that lookup miss, leaked the registry entry, and
every dialog opened afterwards escalated its mask's z-index further above
the panels until dropdowns rendered behind the dialogs hosting them, from
the second dialog open onward. The hook now only raises a panel sitting
below the floor and leaves anything PrimeReact stacked at or above it
untouched, with the decision extracted pure and spec'd.