Update FilterDateTimePicker.php (#1762)

```Filter::datetimepicker()``` has no difference with ```Filter::datepicker()```

With this change there is a time option with Flatpickr

Actually, you should also 'disable' the ```enableTime``` option in ```config/livewire-powergrid.php``` to let these two differ from each other.

To also enable seconds with the datetimepicker you can use:
```
Filter::datetimepicker('created_at')->params(['enableSeconds' => true])
```

src/Components/Filters/FilterDateTimePicker.php

@@ -7,11 +7,13 @@ class FilterDateTimePicker extends FilterBase
 {
     public string $key = 'datetime';
 
-    public array $params = [];
+    public array $params = [
+        'enableTime' => true,
+    ];
 
     public function params(array $params): FilterDateTimePicker
     {
-        $this->params = $params;
+        $this->params = array_merge($this->params, $params);
 
         return $this;
     }