Tags of Sidecar Collector Configurations are not included in Content Pack

## Expected Behavior
Sidecar Collector Configuration:

Content Pack:

`{"v": 1,"id": "6cdfaa77-152c-49d6-880f-a424ab7f24b6","rev": 1,"name": "Graylog Evaluation Sidecar Collection","summary": "Graylog Evaluation Sidecar Collection","description": "Graylog Evaluation Sidecar Collection","vendor": "Graylog Evaluation Sidecar Collection","url": "https://github.com/fjagwitz/Graylog-Cookbooks","parameters": [],"entities": [{"v": "1","type": {"name": "sidecar_collector_configuration","version": "1"},"id": "0f4c522d-dbd8-47cc-96a9-9a1a11a056a2","data": {"collector_id": {"@type": "string","@value": "09a5c47a-1738-42f8-9b94-84edc613d952"},"title": {"@type": "string","@value": "self-beats"},"color": {"@type": "string","@value": "#827717"},"tags": {"@type": "list","@value": ["self-beats"]},"template": {"@type": "string","@value": "# Required settings\nfields_under_root: true[...]`

## Current Behavior

Content Pack:

`{"v": 1,"id": "6cdfaa77-152c-49d6-880f-a424ab7f24b6","rev": 1,"name": "Graylog Evaluation Sidecar Collection","summary": "Graylog Evaluation Sidecar Collection","description": "Graylog Evaluation Sidecar Collection","vendor": "Graylog Evaluation Sidecar Collection","url": "https://github.com/fjagwitz/Graylog-Cookbooks","parameters": [],"entities": [{"v": "1","type": {"name": "sidecar_collector_configuration","version": "1"},"id": "0f4c522d-dbd8-47cc-96a9-9a1a11a056a2","data": {"collector_id": {"@type": "string","@value": "09a5c47a-1738-42f8-9b94-84edc613d952"},"title": {"@type": "string","@value": "self-beats"},"color": {"@type": "string","@value": "#827717"},"template": {"@type": "string","@value": "# Required settings\nfields_under_root: true[...]`

## Possible Solution

Ensure that the Sidecar Tag gets exported in the Content Pack as well.

## Steps to Reproduce (for bugs)

1. Create a Sidecar Collector Configuration Template
2. Assign a Tag to that template
3. Export the Sidecar Collector Configuration Template into a Content Pack
4. Review the Content Pack, it does not contain the tag

## Context

I cannot use Content Packs for Sidecar Collector Configuration Templates in Production.

## Your Environment

* Graylog Version: 7

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