Editing Event Definition from Aggregation to Filter does not Save

A customer reported an issue when trying to edit an existing Event definition, where if they try to change from "Aggregation of results reaches a threshold", to "Filter has results", and tries to Save the modification, it does not appear to save those changes.

## Expected Behavior
After editing and saving modifications to an Event definition, those changes should take effect.

## Current Behavior
The system appears to ignore the changes to the rule.

## Steps to Reproduce (for bugs)
The customer has provided the following instructions for reproducing the issue:

[Event Definition-GUI-bug-report.pdf](https://github.com/user-attachments/files/18990295/Event.Definition-GUI-bug-report.pdf)

## Your Environment

* Graylog Version: 6.1.6