Address CS0656 with latest compiler (#9135)

* Update System.Windows.Input.Manipulations.csproj

* Update UIAutomationTypes.csproj

Author: ericstj

src/Microsoft.DotNet.Wpf/src/System.Windows.Input.Manipulations/System.Windows.Input.Manipulations.csproj

@@ -40,6 +40,7 @@
     <NetCoreReference Include="System.Collections" />
     <NetCoreReference Include="System.Diagnostics.Debug" />
     <NetCoreReference Include="System.Diagnostics.Tools" />
+    <NetCoreReference Include="System.Memory" />
     <NetCoreReference Include="System.Runtime" />
     <NetCoreReference Include="System.Runtime.Extensions" />
     <NetCoreReference Include="System.Resources.ResourceManager" />

src/Microsoft.DotNet.Wpf/src/UIAutomation/UIAutomationTypes/UIAutomationTypes.csproj

@@ -94,6 +94,7 @@
     <NetCoreReference Include="netstandard" />
     <NetCoreReference Include="Microsoft.Win32.Primitives" />
     <NetCoreReference Include="System" />
+    <NetCoreReference Include="System.Memory" />
     <NetCoreReference Include="System.Runtime" />
     <NetCoreReference Include="System.Resources.ResourceManager" />
     <NetCoreReference Include="System.Runtime.InteropServices" />