Disable prebuilds for pull requests.
addComment now defaults to false so we don't need to set it anymore.
Refs: https://github.com/nodejs/node/pull/43789#issuecomment-1182875886
Refs: https://www.gitpod.io/docs/prebuilds#github-specific-configuration
PR-URL: https://github.com/nodejs/node/pull/43829
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>