The previous implementation would send API Sessions to Edge Routers
while partially authenticated. Due to state issues addressed separately
in the c-SDK, these partial API Sessions are maintained if a channel
connected to an edge router was established during reconnect. This would
further cause problems with channel connection using the wrong API
session vs what the rest of the SDK was using.
- as updates to API Sessions can now happen later than the last time
they were active, updatedAt is no longer the correct representation of
the last activity an API Session had
- move all logic that used updatedAt to lastActivityAt
- add migration to set lastActivityAt
Andrew Martinez