BUG: Autocomplete #header slot with autoHighlight option

[aeastburg]

[x] bug report
primevue: 3.8.2
vue: 3.2.20
browser: chrome

Reproduce by creating a primevue using the autoHighlight option.
Add the #header slot and put an element like a

inside.
If you just put text in #header, the autocomplete works. But when it's an element in the slot it will break.

Might be something about autoHighlight option automatically trying to select the first element, but it's now colliding with the unaccounted for header element when #header slot is used.

You'll get this error in console when autocomplete tries to show the overlay. (no overlay is shown)
TypeError: Cannot read properties of null (reading 'classList')
at Object.addClass (utils.esm.js?dd76:123)
at Proxy.onOverlayEnter (autocomplete.esm.js?4084:141)