Dashboards show erroneous `Unknown field` warning despite field being valid.

When executing a query via a Graylog Dashboard, graylog appears to send an XHR req to `POST /api/views/fields`. If the dashboard search does NOT specify a time range override, the above POST req is executed with a default time range of 300s (5m) `{"timerange":{"from":300,"type":"relative"}}`.

When an explicit time range override is used, the warning is no longer present.

https://github.com/user-attachments/assets/d6b088d0-51a7-4725-af6b-4a27236bd00b

## Expected Behavior

Graylog does not show erroneous `Unknown field` warnings

## Current Behavior

Graylog shows erroneous `Unknown field` warnings

## Possible Solution

Have the XHR req for `POST /api/views/fields` take into account the configured time range of widgets.

## Steps to Reproduce (for bugs)

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## Context

When using graylog to review logs i noticed this.

## Your Environment

* Graylog Version: 7.1.6

## Checklist
[] This issue fix need to be backported.
[] Does this issue have **security** implications?

Start at the dashboard request for POST /api/views/fields and compare the default 300-second timerange with the widget's configured override. Reproduce the warning with no explicit time range, then repeat with an override; done means valid fields no longer show erroneous Unknown field warnings in the first case.

Written by the indexing model from the issue text.