Field results auto search does not populate when manually typed in search

When entering a field in search like "user_name:" and field data is present, it does not populate the top searches. If you enter a then backspace, it populates.
If you search "user_" and click the field name "user_name" it will populate the suggested data present.

## Expected Behavior
Should typing the exact field not present the same?
## Current Behavior
As of now it is not working with the behavior noted above.

## Possible Solution
If exact field names are typed with trailing colon, provide the top hits on the data results.

## Steps to Reproduce (for bugs)

https://github.com/user-attachments/assets/8b69b7e4-0e3b-4aa4-be4d-3862c81ba553

## Context
ease of search results

## Your Environment

* Graylog Version: V6.0.4
* Java Version: V17
* OpenSearch Version: V2.12
* MongoDB Version: V6.0
* Operating System: n/a
* Browser version: n/a