Step not reactive after mount

[dmeijboom]

Describe the bug

The Step component inside the Stepper component never updates isSeparatorVisible which means that if there are new Stepss after mount the value will be off resulting in a missing separator.

Pull Request Link

#8378

Reproducer

https://stackblitz.com/edit/primevue-4-vite-issue-template-7wvbhklb?file=src%2FApp.vue

Environment

VueJS

Vue version

3.5.12

PrimeVue version

4.5.4

Node version

v22.21.1

Browser(s)

No response

Steps to reproduce the behavior

1. Setup Stepper with Steps
2. Add or remove Steps dynamically
3. Separator not rendered

Expected behavior

Adding or removing Steps should work reactively and separators should be computed on update.