[2.4.0] Checkmk Werk 16393 created: notification_rule: allow custom plugin names when selecting cancel without a restart

[//]: # (werk v2) # notification_rule: allow custom plugin names when selecting cancel without a restart key | value ---------- | --- date | 2024-02-14T13:46:22+00:00 version | 2.4.0b1 class | fix edition | cre component | rest-api level | 1 compatible | yes We recently made a change that would allow you to create a notification rule, via the REST-API using a custom plugin but also setting the option "cancel_previous_notifications". However, an apache restart was required since we were verifying the custom plugin via the runtime generated schema. This werk fixes this issue by removing this verification from the schema and checking at the endpoint.