Editing AD ED sets it to disabled upon save

In Graylog 6.0.0-alpha.3+424ab1e, when editing an anomaly detector's event definition, it's shown as set to "disabled" upon save, despite making no changes to the event. It's unclear if the event definition is actually disabled or if this is some kind of visual issue.

https://github.com/Graylog2/graylog2-server/assets/2953243/a2a5e215-eb97-4d92-8416-f729d1d476c4

This does not seem to happen on non-AD-associated EDs.

## Your Environment

* Graylog Version: Graylog 6.0.0-alpha.3+424ab1e
* Java Version: Embedded
* OpenSearch Version: 2.12.0
* MongoDB Version: 7.0.6
* Operating System: Debian 12
* Browser version: Version 122.0.6261.112 (Official Build) (arm64)