Revert "[iOS] Change how ItemsViewController.CheckEmptySource checks for item size" (#15476)

* Revert "[iOS] Change how ItemsViewController.CheckEmptySource checks for item size (#15289)"

This reverts commit d22e7d3.

* Delete Issue15287.xaml.cs

Author: jfversluis

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue15287.xaml

@@ -1868,9 +1868,6 @@
       <DependentUpon>MyCollectionView.xaml</DependentUpon>
       <SubType>Code</SubType>
     </Compile>
-    <Compile Include="$(MSBuildThisFileDirectory)Issue15287.xaml.cs">
-      <DependentUpon>Issue15287.xaml</DependentUpon>
-    </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Issue15100.xaml.cs">
       <DependentUpon>Issue15100.xaml</DependentUpon>
     </Compile>
@@ -2426,9 +2423,6 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
-    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue15287.xaml">
-      <SubType>Designer</SubType>
-    </EmbeddedResource>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue15100.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue15287.xaml.cs

@@ -128,7 +128,7 @@ void CheckForEmptySource()
 				// If we're going from empty to having stuff, it's possible that we've never actually measured
 				// a prototype cell and our itemSize or estimatedItemSize are wrong/unset
 				// So trigger a constraint update; if we need a measurement, that will make it happen
-				ConstrainToItemsView();
+				ItemsViewLayout.ConstrainTo(CollectionView.Bounds.Size);
 			}
 		}