chore(windows): crashpad_handler should be shared among Keyman processes

Currently each Keyman process starts its own crashpad_handler. It is apparently possible to share the handler to child processes with [`SetHandlerIPCPipe`](https://crashpad.chromium.org/doxygen/classcrashpad_1_1CrashpadClient.html#a9f1d5d38e9b4f5781e3821551dcc39d5).

Need to figure out if this works with [Sentry Native](https://github.com/getsentry/sentry-native/blob/master/README.md) as the change may need to be made there.