400 error `cannot update gcal event without id` after editing an event in Compass

[tyler-dane]

Where did this happen?

Hosted (app.compasscalendar.com), Local code with an up-to-date main branch

Expected Behavior

After a user creates a Compass event in an account that's connected to Google, they should be able to create a new compass event and then edit it

Current Behavior

After creating a Compass event, the user gets a 204 No Content from the POST request, but then a 400 for the PUT request with no response body.

Steps to Reproduce

1. Create a Compass event
2. Wait for the backend to process it. The logs will show something like this

0|backend  | 26-03-02 00:05:23 [debug] app.gcal.sync.processor: Processing 1 event(s)...
0|backend  | 26-03-02 00:05:23 [info] app.gcal.sync.processor: Handle Gcal event(REDACTED): STANDALONE->>STANDALONE_CONFIRMED
0|backend  | 26-03-02 00:05:23 [info] app.event.classes.gcal.parser: UPSERTING STANDALONE->>STANDALONE_CONFIRMED: REDACTED (Gcal)
0|backend  | PROCESSED: [
0|backend  |   {
0|backend  |     title: 'yui789',
0|backend  |     transition: [ 'STANDALONE', 'STANDALONE_CONFIRMED' ],
0|backend  |     category: 'STANDALONE',
0|backend  |     operation: 'STANDALONE_UPDATED'
0|backend  |   }
0|backend  | ]
0|backend  | 26-03-02 00:05:23 [info] app:sync.service: GCal Notification for user: 69177bd4b6b879113d279d5d, calendarId: REDACTED@gmail.com PROCESSED AND NOTIFIED CLIENT

3. Edit the new event in Compass
4. See backend error about how the event doesn't have a google id

Possible Solution

Could be related to optimistic rendering and how we need to update the client with the correct google event id once it's created.

Context

Marked needs more info due to not being able to reproduce consistently