2.0.0-rc.7 optimistic lanes don't entangle properly

[GabbeV]

Describe the bug

Two optimistic value updates should entangle when read in the same memo but doesn't leading to the memo revealing a calculation based on both before both are ready to reveal.

Your Example Website or App

https://s.olid.uk/id/Au-Hf9TFQuCwK-gk5e-ryQ

Steps to Reproduce the Bug or Issue

1. Open repro
2. Click button
3. Observe that Pair shows 1:1 before both when only B shows 1 but A is still at 0

Expected behavior

optimistic value updates should entangle just like normal signal updates

Screenshots or Videos

No response

Platform

• OS: Windows
• Browser: Firefox

Additional context

No response

[mizulu]

https://s.olid.uk/id/jLeCMObWTEC3vvuQLZI1HA @ aa523d8