Update fork for ReactSharedInternalsClient export (#27717)

## Summary

After changes in https://github.com/facebook/react/pull/27436, UMD
builds no longer expose Scheduler from ReactSharedInternals. This module
is forked in rollup for UMD builds and the path no longer matches. This
PR updates the path name to match the new module:
ReactSharedInternalsClient.

## How did you test this change?

- `yarn build`
- Inspect `react.development.js` UMD build, observe `Scheduler:
Scheduler` is set in `ReactSharedInternals`, matching
[18.2.0](https://unpkg.com/[email protected]/umd/react.development.js)
- ran attribute-behavior fixture app
- Observe no more error `Uncaught (in promise) TypeError: Cannot read
properties of undefined (reading 'unstable_cancelCallback')`

Co-authored-by: Jack Pope <[email protected]>