dillon1000/react

Remove unnecessary (and incorrect) code for compatibility with Paper in the Fabric version of GlobalResponderHandler (#26290)

## Summary

I'm working on a refactor of the definition of `Instance` in Fabric and
I came across this code that seemed to be for compatibility with Paper,
but that it would actually throw an error in that case.

In Paper, `stateNode` is an instance of `ReactNativeFiberHostComponent`,
which doesn't have a `canonical` field. We try to access nested
properties in that field in a couple of places here, which would throw a
type error (cannot read property `_nativeTag` of `undefined`) if we
actually happened to pass a reference to a Paper state node.

In this line:

```javascript
const isFabric = !!(
      fromOrToStateNode && fromOrToStateNode.canonical._internalInstanceHandle
    );
```

If it wasn't Fabric, `fromOrToStateNode.canonical` would be undefined,
and we don't check for that before accessing
`fromOrToStateNode.canonical._internalInstanceHandle`. This means that
we actually never use this logic in Paper or we would've seen the error.

## How did you test this change?

Existing tests.