fix: favorite reactivity

[hamza221]

Ho to test:

1. checkout feat: pin favorites #12111
2. Have favorite and non favorite messages in a mailbox
3. toggle favorite state for one message and watch it not update pinned state
4. cherry-pick this commit and test again

[ChristophWurst]

Tested and works.

In the inbox the flagged message moves as expected

If I'm not mistaken there can be cases where we introduce phantom messages with this frontend-only reordering.

Example (consiser the number behind the msg as the timestamp):

• Flagged
  • msg 11
  • msg 10
• Other
  • msg 27
  • msg 26
  • msg 25 (not loaded from the server yet)

^ if you unfav 11 or 10 it will go below 26. 25 will never be loaded. it's a phantom.

IMO you can't do this front-end only. We also don't do that in the priority inbox AFAIK.

[GVodyanov]

I looked into this and yes this is an issue, but seeing as messages do get sorted into the favourite section on mailbox sync, the feature is considered ready to release by Christoph.

Therefore, seeing as this isn't considered high priority anymore, I will be unassigning myself.