[HOLD #8503] [Tracking] [Performance] Enable React 18

[roryabraham]

Problem

React 18 introduces a lot of new features that improve performance. Some of those, such as "Automatic Batching" come out-of-the-box for free, and others such as Suspense, startTransition, and useSyncExternalStore are opt-in.

However, we can't use the opt-in features until React 18 is supported on all platforms.

Solution

Enable React 18 on all platforms. This involves a number of tasks:

• [HOLD for payment 2024-04-25] [Tracking] [Performance] Enable the new Fabric architecture #8503
• Upgrade react-native-web to the as-yet-unreleased 0.19, or port over the necessary changes into our fork if we don't want to wait.
  • Deprecate Touchables in favor of Pressable – Deprecate Touchables necolas/react-native-web#2382 this is in-scope for using RNW 0.19

[roryabraham]

Branched this issue off from #8503 for a more correct separation of concerns.

[roryabraham]

No update for now but there's a milestone here. Going to make this a monthly while we're waiting.

[sakluger]

Noting that @aneequeahmad reported this bug first, so they are eligible for a reporting bonus. @roryabraham feel free to assign me to the issue when it's just about completed so I can create and link an Upwork job.

[JmillsExpensify]

@roryabraham Now that we've removed Fabric from WAQ, I'm kind of thinking we should remove React 18 from the initiative as well. Obviously we still need to do this, and related there are performance improvements, but this is still bleeding edge. Do you agree with that?