Add missing isNotAllTime() method to DateRange

[joshhanley]

The problem

We have documented that a isNotAllTime() method exists on the DateRange object, but it doesn't actually exist.

https://fluxui.dev/components/date-picker#all-time

If you are using this date range to filter data, you may want to remove "where" constraints from the query when allTime is selected:

<?php

$orders = Order::when($this->range->isNotAllTime(), function ($query) => {
    $query->whereBetween('created_at', $this->range);
})->get();

The solution

This PR adds it.

public function isNotAllTime(): bool
{
    return $this->preset !== DateRangePreset::AllTime;
}

Fixes #1164