fix: Duplicate crashed sessions

[timfish]

Closes #941. Maybe also #931 and #895.

I re-read through all the Sentry SDK development docs around sessions and found this:

A session can exist in two states: in progress or terminated. A terminated session must not receive further updates. exited, crashed and abnormal are all terminal states. When a session reaches this state the client must not report any more session updates or start a new session.

The Electron SDK was not following this as it was sending further updates after the initial crashed session was sent. I would not have expected these updates to be counted as new sessions since the sid doesn't change and init is never true more than once.

Make no assumptions and read the docs thoroughly!

[Lms24]

Good catch! I had no idea about this either but TIL