Remove Extra Space Before "stackTrace" in Error Payload JSON

[math-hiyoko]

Summery

This PR addresses the issue reported in #197 regarding the unnecessary space found before the "stackTrace" key in the generated JSON error payload. The presence of this space affects the consistency of the JSON formatting without impacting the functionality or parseability of the output. This minor change aims to enhance the readability and the overall quality of the code by maintaining a consistent JSON format.

Changes

The extra space before the "stackTrace" key in the JSON string construction has been removed.

Before

R"(", "stackTrace":[]})";

After

R"(","stackTrace":[]})";