fix possible memory leaks

src/core/shuntingYard.cpp

@@ -782,8 +782,8 @@ std::string compute(const std::string & expr) {
                     expr_new.replace(f, e - f, result.c_str());
                 }
                 http->end();
-                delete http;
             }
+            delete http;
         }
         f = expr_new.find_first_of('{', e);
     }

src/web/WebSchedulerService.cpp

@@ -401,6 +401,7 @@ bool WebSchedulerService::command(const char * name, const std::string & command
             return true;
         }
         // we can add other json tests here
+        delete http;
     }
 
     doc.clear();

src/web/WebStatusService.cpp

@@ -245,6 +245,7 @@ void WebStatusService::action(AsyncWebServerRequest * request, JsonVariant json)
     if (!ok) {
         EMSESP::logger().err("Action '%s' failed", action.c_str());
         request->send(400); // bad request
+        delete response;
         return;
     }