Fix error header for bidirectional streaming models

Author: SergeyRyabinin

tools/code-generation/generator/src/main/resources/com/amazonaws/util/awsclientgenerator/velocity/cpp/ModelClassMembersAndInlines.vm

@@ -14,6 +14,9 @@
 #if($CppViewHelper.isStreamingPayloadMember($shape, $member.key) && $shape.result)
 #set($cppType = "Aws::Utils::Stream::ResponseStream")
 #set($isStream = true)
+#elseif($member.value.shape.isException() && !$member.value.shape.isModeledException())
+#set($cppType = "${metadata.classNamePrefix}Error")
+#set($isStream = false)
 #else
 #set($cppType = $CppViewHelper.computeCppType($member.value.shape))
 #set($isStream = false)

tools/code-generation/generator/src/main/resources/com/amazonaws/util/awsclientgenerator/velocity/cpp/common/model/ServiceClientModelHeaderMemberDeclaration.vm

@@ -7,6 +7,9 @@
 #set($isEventStreamInput = false)
 #end
 #set($cppType = $CppViewHelper.computeCppType($shape, $member.key))
+#if($member.value.shape.isException() && !$member.value.shape.isModeledException())
+#set($cppType = "${metadata.classNamePrefix}Error")
+#end
 #set($memberVariableName = $CppViewHelper.computeMemberVariableName($member.key))
 #if($member.value.shape.getName() == $shape.getName() && $member.value.shape.list)
     Aws::Vector<$cppType> $memberVariableName;