fix for empty expression primitive type serialization

Signed-off-by: chcurran <82187351+carlitosan@users.noreply.github.com>

Gems/ExpressionEvaluation/Code/Source/ExpressionPrimitivesSerializers.inl

@@ -28,6 +28,19 @@ namespace AZ
     private:
         using VariableDescriptor = ExpressionEvaluation::ExpressionTree::VariableDescriptor;
 
+        static constexpr AZStd::string_view EmptyAnyIdentifier = "Empty AZStd::any";
+
+        static bool IsEmptyAny(const rapidjson::Value& typeId)
+        {
+            if (typeId.IsString())
+            {
+                AZStd::string_view typeName(typeId.GetString(), typeId.GetStringLength());
+                return typeName == EmptyAnyIdentifier;
+            }
+
+            return false;
+        }
+
         JsonSerializationResult::Result Load
             ( void* outputValue
             , [[maybe_unused]] const Uuid& outputValueTypeId
@@ -62,6 +75,8 @@ namespace AZ
                         , JsonSerialization::TypeIdFieldIdentifier));
             }
 
+            if (!IsEmptyAny(typeIdMember->value))
+            {
                 result.Combine(LoadTypeId(typeId, typeIdMember->value, context));
                 if (typeId.IsNull())
                 {
@@ -78,6 +93,7 @@ namespace AZ
 
                 result.Combine(ContinueLoadingFromJsonObjectField(AZStd::any_cast<void>(&storage), typeId, inputValue, "Value", context));
                 outputDatum->m_value = storage;
+            }
             // any storage end
 
             return context.Report(result, result.GetProcessing() != JSR::Processing::Halted
@@ -123,6 +139,8 @@ namespace AZ
                 , azrtti_typeid<decltype(inputScriptDataPtr->m_supportedTypes)>()
                 , context));
 
+            if (!inputScriptDataPtr->m_value.empty())
+            {
                 rapidjson::Value typeValue;
                 result.Combine(StoreTypeId(typeValue, inputScriptDataPtr->m_value.type(), context));
                 outputValue.AddMember
@@ -137,6 +155,16 @@ namespace AZ
                     , defaultScriptDataPtr ? AZStd::any_cast<void>(const_cast<AZStd::any*>(&defaultScriptDataPtr->m_value)) : nullptr
                     , inputScriptDataPtr->m_value.type()
                     , context));
+            }
+            else
+            {
+                rapidjson::Value emptyAny;
+                emptyAny.SetString(EmptyAnyIdentifier.data(), aznumeric_caster(EmptyAnyIdentifier.size()), context.GetJsonAllocator());
+                outputValue.AddMember
+                    ( rapidjson::StringRef(JsonSerialization::TypeIdFieldIdentifier)
+                    , AZStd::move(emptyAny)
+                    , context.GetJsonAllocator());
+            }
 
             return context.Report(result, result.GetProcessing() != JSR::Processing::Halted
                 ? "VariableDescriptor Store finished saving VariableDescriptor"