Reverting error check and comment

cmake/LYWrappers.cmake

@@ -692,7 +692,9 @@ endfunction()
 # given a target name, returns the "real" name of the target if its an alias.
 # this function recursively de-aliases
 function(ly_de_alias_target target_name output_variable_name)
+    # its not okay to call get_target_property on a non-existent target
     if (NOT TARGET ${target_name})
+        message(FATAL_ERROR "ly_de_alias_target called on non-existent target: ${target_name}")
     endif()
 
     while(target_name)