[2.3.0] Checkmk Werk 16785 created: notification rules: allow for the global http proxy configuration for plugins

[//]: # (werk v2) # notification rules: allow for the global http proxy configuration for plugins key | value ---------- | --- date | 2024-05-27T10:31:46+00:00 version | 2.3.0p5 class | fix edition | cre component | rest-api level | 1 compatible | no When configuring a notification rule with one of the following plugins * Cisco Webex Teams * iLert * MS Teams * PagerDuty * Splunk On-Call * SIGNL4 Alerting the option to select a globally configured http proxy was not possible via the REST-API. This werk addresses this issue and you can now select a globally configured http proxy for any of the mentioned plugins.