fix: hide navigation in "time" mode

[valh1996]

This PR will hide navigation buttons in time mode (not date).

For more complex needs, it may be useful to use the Calendar component in time only mode. In particular, to be able to customize the appearance more easily, example :

<Calendar 
  type="range"
  v-model.range="form.date.range" 
  mode="date" 
  :columns="2"
>
<template #footer>
  <div class="w-full">
    Entry time:
    <Calendar 
      v-model="form.date.range.start" 
      mode="time" 
      hide-time-header
      is24hr
    />
    Exit time:
    <Calendar 
      v-model="form.date.range.end" 
      mode="time" 
      hide-time-header
      is24hr
    />
  </div>
</template>
</Calendar>

The problem is that without this fix, the navigation chevrons appear:

[hrynevychroman]

🔥 needed feature 💯

[sadeghbarati]

Thanks!

Hope props and attrs merge later in Vue cause this abstraction makes things harder