fix build pipeling

Author: vgromfeld

UnitTests/UnitTestApp.xaml

@@ -1,5 +1,17 @@
 <Application x:Class="UnitTests.App"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:controls="using:Microsoft.Toolkit.Uwp.UI.Controls"
+             xmlns:ex="using:Microsoft.Toolkit.Uwp.UI.Extensions"
              xmlns:local="using:UnitTests"
-             RequestedTheme="Light" />
+             RequestedTheme="Light">
+
+    <Application.Resources>
+        <!--
+            We need to manually import some types here to force the XAML compiler to add them to the XamlTypeInfo file.
+            This is needed only when dynamically loading controls that the XAML compiler cannot find (ie using XamlReader.Load to load the controls).
+        -->
+        <Style TargetType="controls:UniformGrid" />
+        <ex:NullableBool x:Key="nullableBool" />
+    </Application.Resources>
+</Application>