Undo typo fix

Author: captainsafia

src/Mvc/Mvc.Testing/src/Microsoft.AspNetCore.Mvc.Testing.targets

@@ -46,7 +46,7 @@
     </ItemGroup>
   </Target>
 
-  <Target Name="CopyAdditionalFiles" AfterTargets="Build;_ResolveMvcTestProjectReferences" Condition="'$(TargetFramework)'!=''">
+  <Target Name="CopyAditionalFiles" AfterTargets="Build;_ResolveMvcTestProjectReferences" Condition="'$(TargetFramework)'!=''">
     <ItemGroup>
       <DepsFilePaths
         Condition="'%(_ContentRootProjectReferences.Identity)' != ''"