monitor-new-issues should ping the Issue Triager Oncall (#49359)

Summary:
This updates the Issue Triaging bot to ping the oncall

## Changelog:

[INTERNAL] -

Pull Request resolved: https://github.com/facebook/react-native/pull/49359

Test Plan: Nothing to test

Reviewed By: cipolleschi

Differential Revision: D69527137

Pulled By: cortinico

fbshipit-source-id: 7291054a734bf9f7240002773b716b2057aa8eca