Merge pull request #570 from aws-lumberyard-dev/mp_split_cmake

Add Unified alias for upcoming Multiplayer UnifiedLauncher changes

Gem/Code/CMakeLists.txt

@@ -50,6 +50,7 @@ ly_add_target(
 # if enabled, AtomSampleViewer is used by the Client and ServerLauncher
 ly_create_alias(NAME AtomSampleViewer.Clients  NAMESPACE Gem TARGETS Gem::AtomSampleViewer)
 ly_create_alias(NAME AtomSampleViewer.Servers  NAMESPACE Gem TARGETS Gem::AtomSampleViewer)
+ly_create_alias(NAME AtomSampleViewer.Unified  NAMESPACE Gem TARGETS Gem::AtomSampleViewer)
 
 if(PAL_TRAIT_BUILD_HOST_TOOLS)