Namespaced cron_schedules callbacks not detected

Bug Description

The WordPress.WP.CronInterval sniff is producing a warning when a namespaced callback is used: "Detected changing of cron_schedules, but could not detect the interval value."

Minimal Code Snippet

namespace Foo {
	function my_add_every_hour( $schedules ) {
		$schedules['every_hour'] = [
			'interval' => HOUR_IN_SECONDS,
			'display' => __( 'Once every hour' )
		];
		return $schedules;
	}
	add_filter( 'cron_schedules', __NAMESPACE__ . '\my_add_every_hour'); // OK: > 10 min.
}

Environment

Tested Against develop branch?

• I have verified the issue still exists in the develop branch of WPCS.

Start with the WordPress.WP.CronInterval sniff and reproduce the warning using the namespaced PHP example from the issue. Trace how the cron_schedules callback and interval are detected, then verify that the namespaced callback no longer triggers the warning while the interval is recognized on the develop branch.