[RefreshView] Fire RefreshCommand setting IsRefreshing (#7398)
* refresh view ui tests
* Fixed issue notifying changes in IsRefreshing property
* Fire RefreshCommand setting IsRefreshing to true
* Update Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
* Update Xamarin.Forms.Core.UITests.Shared/UITestCategories.cs
* Added RefreshView UITests
* - ui test with swipe
* - change to drag
* - fix ui test
* - remove extra property changed event