telemetry_json: Remove unnecessary includes

Removes unused includes. Also rectifies a missing <chrono> include.

src/web_service/telemetry_json.h

@@ -5,10 +5,10 @@
 #pragma once
 
 #include <array>
+#include <chrono>
 #include <string>
 #include <json.hpp>
 #include "common/telemetry.h"
-#include "common/web_result.h"
 
 namespace WebService {