Related to tracker issue:
- https://github.com/flutter/flutter/issues/128251

This event was only called from one file (`flutter_command.dart`). With the previous implementation, we actually sent 2 events, one for the result of the `commandPath` and another containing the `maxRss` value from `ProcessInfo`.

I have consolidated this down to just one event and used a function to safely get the `maxRss` value, or return null when if there was an error getting that integer value