Check for notification level depth

[carmas123]

Hi please can you add a level depth check into _onNotifcation method.
If you have a list with animated widget that scroll vertically this method is calle endlessly and also _loadMore.

The changes to do are these:
At row 61 of lazy_load_scrollview.dart

if (widget.scrollDirection == notification.metrics.axis) {

should turn into

if (widget.scrollDirection == notification.metrics.axis && defaultScrollNotificationPredicate(notification)) {

This check if the scroll came from the real list scroll and not from a scrollable item into it.

Regards
Massimo

[QuirijnGB]

Heya,

Thanks for that! Can you create a PR for it, so you can get credit