Docs: slack setup images

[isadeks]

Doc area

User guide (docs/guides/USER_GUIDE.md or synced site)

Describe the issue

The screenshot images do not load when displayed on the documentation site. The images show up in the markdown file, https://github.com/aws-samples/sample-autonomous-cloud-coding-agents/blob/main/docs/guides/SLACK_SETUP_GUIDE.md

Affected docs

https://aws-samples.github.io/sample-autonomous-cloud-coding-agents/using/slack-setup-guide/

Suggested change

No response