[MM-61776] Fix errcheck issues in server/channels/app/platform/web_conn.go (#29515)

server/.golangci.yml

@@ -101,7 +101,6 @@ issues:
         channels/app/platform/session.go|\
         channels/app/platform/status.go|\
         channels/app/platform/web_broadcast_hook.go|\
-        channels/app/platform/web_conn.go|\
         channels/app/platform/web_hub.go|\
         channels/app/platform/web_hub_test.go|\
         channels/app/plugin_test.go|\