chore(ci): Switch to PR Reviews for triggering CI (#20892)

* chore(ci): Switch to PR Reviews for triggering CI

Allows us to capture the correct SHA to run CI with.

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

* PR feedback

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

* use startsWith rather than contains

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

---------

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>