dillon1000/react

Extract duplicated methods in Fabric and the legacy renderer to a shared module (#26319)

## Summary

The following methods have exactly the same implementation on Fabric and
the legacy renderer:
* `findHostInstance_DEPRECATED`
* `findNodeHandle`
* `dispatchCommand`
* `sendAccessibilityEvent`

This just extracts those functions to a common module so they're easier
to change (no need to sync changes in 2 files).

## How did you test this change?

Existing tests (this is a refactor).