Cannot sort data table widget with more than 1 field

It appears that it is only possible to sort a data table widget using a single field, even though the UX suggests that it can and will sort by more than 1 field.


## Expected Behavior

If data table shows the ability to sort multiple fields, sorting is applied as expected. For example, if i sort by timestamp, and then sum(network_bytes), this sorting should be applied.


## Current Behavior

Data table widget only allow sorting by 1 single field.

## Possible Solution

## Steps to Reproduce (for bugs)

1. Create a data table widget
2. Attempt to sort by more than 1 field

Alternatively:

1. edit data table widget
2. add more than 1 sort field
3. observe that field select/dropdown does not allow you to select a field for second sort field input

## Context

Via https://community.graylog.org/t/sort-additional-metrics-when-sort-timestamp-is-enabled-not-working/28627

## Your Environment

* Graylog Version: Graylog 5.0.6+51f2df8
* Java Version: Bundled JDK
* ~~Elasticsearch~~OpenSearch Version: 2.6.0
* MongoDB Version: 6.0.5
* Operating System: Ubuntu Server 22.04 LTS
* Browser version: Google Chrome Version 112.0.5615.137 (Official Build) (arm64)