Remove legacy Paper renderer shim cleanup from artifact commit workflow (#36297)

## Summary PR #36285 deleted the Paper (legacy) renderer, including the shim file `scripts/rollup/shims/react-native/ReactNative.js`. However, the `runtime_commit_artifacts` workflow still tries to `rm` this file after moving build artifacts into `compiled-rn/`. Since the file no longer exists in the build output, `rm` (without `-f`) fails and kills the entire step. This has caused **every run of the Commit Artifacts workflow to fail since #36285 landed on April 16**, blocking both `builds/facebook-www` and `builds/facebook-fbsource` branches from receiving new build artifacts. This in turn blocks DiffTrain from syncing React changes into Meta's internal monorepo.