QE-1993 fix undefined updateNavItems error in TP slider

[i-am-chitti]

This PR fixes undefined function type error in TP slider -

Background

When working with Web Components/Custom Elements, there's an asynchronous upgrade process that can cause race conditions. Elements queried via querySelector immediately after DOM insertion may not have their custom methods available yet, resulting in TypeError: undefined is not a function errors.

Root Cause: Per the HTML specification, custom element upgrades occur asynchronously. When elements are created (either on initial page load or via innerHTML/AJAX injection), there's a brief window where:

1. The element exists in the DOM as a plain HTMLElement
2. querySelector successfully returns the element
3. Custom element constructors haven't executed yet
4. Custom methods/properties are undefined

Replication - https://codeshare.io/2j6nYA

This is what causing issue in tp-slider component -

web-components/src/slider/tp-slider.ts

Line 427 in 3d535a3

sliderNav?.updateNavItems();

Slack discussion - https://travelopia-it.slack.com/archives/C089GHT0ETV/p1759816852454069?thread_ts=1759816472.395389&cid=C089GHT0ETV