Summary:
Newer versions of Buck (not released open source) support an `oncall` annotation to denote who owns a particular BUCK file. These annotations are useful to support so that if BUCK files are updated with such annotations they don't break.

## Changelog

[Internal] [Changed] - support oncall annotation in BUCK files

Pull Request resolved: https://github.com/facebook/react-native/pull/35562

Test Plan: The `test_buck` CI job validates that the file can be evaluated by open-source Buck. I ran this on a CircleCI fork, and it passed.

Reviewed By: motiz88

Differential Revision: D41731925

Pulled By: cortinico

fbshipit-source-id: 7d0ae164c3e6289d4aa76892658d46bbe4faf99c