[cpprest-sdk] avoid newlines when no model import

Author: aminya

modules/openapi-generator/src/main/resources/cpp-rest-sdk-client/apiclient-header.mustache

@@ -13,7 +13,9 @@
 #include "{{packageName}}/ApiException.h"
 #include "{{packageName}}/IHttpBody.h"
 #include "{{packageName}}/HttpContent.h"
-{{^hasModelImport}}#include "{{packageName}}/ModelBase.h"{{/hasModelImport}}
+{{^hasModelImport}}
+#include "{{packageName}}/ModelBase.h"
+{{/hasModelImport}}
 #if  defined (_WIN32) || defined (_WIN64)
 #undef U
 #endif