When calling resolveKeyserverSessionInvalidationUsingNativeCredentials, we should pass a getInitialNotificationsEncryptedMessage that can take a InitialNotifMessageOptions param.
We have several callsites where we don't type this correctly. Flow didn't catch it for some reason.. I guess from Flow's perspective, a function that can optionally take 1 param is a valid thing to pass as a function that takes no params.
Depends on D10689