Add an LyShine client API target (#6829)

* Reduce the need to link with LyShine static lib in other gems

Signed-off-by: abrmich <abrmich@amazon.com>

* Add UiBasics.Builders to VirtualGamepad.Builders alias

Signed-off-by: abrmich <abrmich@amazon.com>

* Add UiBasics to LyShine gem's metadata

Signed-off-by: abrmich <abrmich@amazon.com>

* Change include to a forward declaration

Signed-off-by: abrmich <abrmich@amazon.com>

Gems/MessagePopup/Code/CMakeLists.txt

@@ -19,7 +19,7 @@ ly_add_target(
     BUILD_DEPENDENCIES
         PUBLIC
             Legacy::CryCommon
-            Gem::LyShine
+            Gem::LyShine.Clients.API
 )
 
 ly_add_target(
@@ -39,4 +39,4 @@ ly_add_target(
 
 # MessagePopup is used only in client applications
 ly_create_alias(NAME MessagePopup.Clients NAMESPACE Gem TARGETS Gem::MessagePopup)
-
+ly_create_alias(NAME MessagePopup.Builders NAMESPACE Gem TARGETS Gem::UiBasics.Builders)