DatePicker: buttonBar for time-only variant shows meaningless "Today" button

[jasonfellows]

Describe the bug

When using DatePicker's timeOnly variant with showButtonBar enabled, both "Today" and "Clear" buttons are included, but "Today" has no meaning with a date.

"Clear" remains very useful. We would like to render the buttonBar for timeOnly Datepickers without the "Today" button by default to avoid needing passthrough to control its visibility.

Pull Request Link

#7334

Reproducer

https://stackblitz.com/edit/primevue-4-vite-issue-template-h3e3k76w?file=src%2FApp.vue

Environment

The bug is reproducible with any client of PrimeVue v4 (Chome MacOS Nuxt 3 app in my case)

Vue version

3.x.x

PrimeVue version

4.x.x

Node version

x.x.x

Browser(s)

No response

Steps to reproduce the behavior

1. Render DatePicker with timeOnly="true" and showButtonBar="true"
2. Click on the input
3. View the "Today" button rendered without a calendar present

Expected behavior

When timeOnly="true", the buttonBar contains only the "Clear" button.