Create Event Definition "Search within" Always NaN for Sources Dashboard

Clicking "Create event definition" for any value on any view on the "Sources" Dashboard always results in `Search within ms: NaN`.
Continuing to Event Definition always results in defaulting "Search within" to 1 second.
Adding/updating the global or widget time ranges does not change the above.

This works as expected an any other dashboard and view outside the Sources Dashboard.


## Expected Behavior

The Event Definition `Search within ms` reflects the time range of the Dashboard or view.

## Current Behavior

## Possible Solution

## Steps to Reproduce (for bugs)

1. Go to the "Sources" Dashboard
2. Click the action menu for a value in any view
3. Click "Create event definition"
4. Observe `Search within ms: NaN`

## Context

## Your Environment

* Graylog Version:
* Java Version:
* OpenSearch Version:
* MongoDB Version:
* Operating System:
* Browser version: