Don't refresh the search when editing a widget

## What?

Currently, clicking `Edit` on a widget (e.g. the default bar chart when doing a search) appears to trigger a new search execution. This request is to _not_ do that search if data is already available, reducing load on the search cluster and improving the user experience when editing widgets.

## Why?

When starting out with a search that takes a noticeable amount of time to complete, the additional search/refresh that occurs:
1. Introduces unnecessary load on the search cluster ("why is it doing another full search when it already has the data?")
2. Negatively impacts the user experience ("why am I waiting 20 seconds for existing data to reload?", "why did the widget config changes I made get reverted as soon as the data reloaded?")

A workaround has been to significantly reduce the search window before editing the widget, however that's not ideal (due to additional steps + potential impact to how the widget results appear when editing).

Seems somewhat related to #18122.

## Your Environment

* Graylog Version: `6.0.1`