Fix implicit layout animations during modal presentation

[SzymczakJ]

Summary

When a React Navigation native stack screen is presented as a modal, UIKit's presentViewController:animated:YES creates an animation context (~350ms) that causes React Fabric's async layout updates to be implicitly animated, resulting in visible "fly-in" animations on views and scale animations on text.

This adds two fixes:

• Wrap center/bounds assignments in updateLayoutMetrics: with a CATransaction that disables implicit animations
• Add actionForLayer:forKey: override to RCTParagraphTextView to disable implicit layer animations on text views

Tracked in https://app.asana.com/1/236888843494340/project/1199705967702853/list/1204187545226790