Field suggestion in search should not display all fields

## Expected Behavior
When you use the field suggestion inside of a stream it should only display fields that are visible/used inside of that stream.

## Current Behavior
Graylog suggestion from all fields that are available.

## Context
If you run Graylog with multiple user groups with seperated data and restricted access to data, it might be a security risk having all available fields exposed. In addition it will confuse users because they see field names their specific view did not include and the product looks broken/unuseable to them.

## Your Environment

* Graylog Version: 2.4.3