\core\hook\backup\get_excluded_events():

• wrong namespace - it should be \core_backup\hook located in backup\util\ui\classes
• wrong naming
• poor naming for add_events because we are excluding events
• use of an array of strings rather than a varidic

IN addition I discovered a bug whereby the creation of this hook has lead to an event bleed between iterations of the hook beacuse the $params are modified between array iterations. As a result, if multiple readers are enabled, with the legacy logstore being last, the legacy logstore will also ignore the event when it should not do so.

Changes proposed:

• move to correct namespace
• rename to before_course_modified_check
• rename get_excluded_events::add_events(string[] $events) to before_course_modified_check::exclude_events(string ...$events)
• fix the $params bleed.