identity: fix expired session deletion

[calebdoxsey]

Summary

I think we were deleting a session when a user refresh failed and then immediately re-adding it. These changes remove the session from the session collection in addition to deleting it so that we don't attempt to refresh these session.

Related issues

Fixes https://github.com/pomerium/internal/issues/1207

Checklist

• reference any related issues
• updated unit tests
• add appropriate tag (improvement / bug / etc)
• ready for review

[coveralls]

Coverage: 62.937% (+0.05%) from 62.883% when pulling d3712e2 on cdoxsey/fix-delete-session into e019885 on main.

[calebdoxsey]

Seems to fix the problem:

{"level":"info","config_file_source":"/home/caleb/src/github.com/calebdoxsey/pomerium-notes/2023/01/05/config.json","bootstrap":true,"service":"identity_manager","user_id":"calebdoxsey","session_id":"1fa43a5d-1bd6-4f1c-a2dd-e75f7409bf05","time":"2023-01-05T11:34:42-07:00","message":"refreshing session"}
{"level":"info","config_file_source":"/home/caleb/src/github.com/calebdoxsey/pomerium-notes/2023/01/05/config.json","bootstrap":true,"service":"identity_manager","user_id":"calebdoxsey","session_id":"1fa43a5d-1bd6-4f1c-a2dd-e75f7409bf05","time":"2023-01-05T11:34:42-07:00","message":"deleting expired session"}
{"level":"info","type":"type.googleapis.com/session.Session","id":"1fa43a5d-1bd6-4f1c-a2dd-e75f7409bf05","time":"2023-01-05T11:34:42-07:00","message":"get"}
{"level":"info","record-type":"type.googleapis.com/session.Session","record-id":"1fa43a5d-1bd6-4f1c-a2dd-e75f7409bf05","time":"2023-01-05T11:34:42-07:00","message":"put"}