PostFlightPayload unmarshalling errors

[cabillman]

In testing the latest moroz in our environment I noticed different santa clients encode the PostflightPayload differently.

Version 24.6 sends the following json: {"rules_received":"1","rules_processed":"1","machine_id":"xxxx"}

This ends up causing the client to hang retrying to the request 5 times while the server logs
{"caller":"mux.go:159","err":"json: cannot unmarshal string into Go struct field PostflightPayload.rules_received of type int","severity":"info","ts":"2025-05-06T17:31:01.853347761Z"}

I think this santa pull request is the culprit - google/santa#1415

I confirmed running santa client version 24.9 does solve this problem.

Do you have thoughts on making the server more robust so that it can handle both formats? I can try and put together a pull request.

Thanks!

[cabillman]

I submitted a similar pull request for the EventUploadEvent