Fixes an issue where Ivy incorrectly inserts items in the beginning of an `ngFor`, if the `ngFor` is set on an `ng-container`. The issue comes from the fact that we choose the `ng-container` comment node as the anchor point before which to insert the content, however the node might be after any of the nodes inside the container. These changes switch to picking out the first node inside of the container instead.
PR Close#32324