fix endpoint status logging

[Jumpy-Squirrel]

We have some endpoints that do not correctly log success status 200, instead they log 0.

Only affects logging.

Cause: This happends if the endpoint implementation neither calls WriteHeader nor writes a response body. http.Server still sends a default status 200, but the request wrapper used to record the status for logging doesn't know this, and logs 0.

Solution: explicitly call w.WriteHeader(http.StatusOK) at the end of the endpoint handler. It's clearer anyway.