[Bug][iOS] listview / observable collection throwing native error on load (#6576)
* Added reproduction and commented out the misbehaving code
* Fixed merge conflicts
# Conflicts:
# Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
* Implemented UI test
* Somehow merged in a non-existing UI test
* Removed DetermineEstimatedRowHeight in WillDisplay
* Revert "Removed DetermineEstimatedRowHeight in WillDisplay"
This reverts commit
431178d923c3bf642aae83331a5dc5b57c4436de.
* Removed WillDisplay with DetermineEstimatedRowHeight
* Reinstate projitems
* Added some more test scenarios
* Removed commented code
* Update Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue6472.cs
fixes #6472