errcheck issues fixed (#28609)

server/.golangci.yml

@@ -106,7 +106,6 @@ issues:
         channels/api4/user.go|\
         channels/api4/user_local.go|\
         channels/api4/user_test.go|\
-        channels/api4/webhook.go|\
         channels/api4/webhook_test.go|\
         channels/api4/websocket_test.go|\
         channels/app/admin.go|\