Update roadie-backstage-plugins workspace to commit 794d6da for backstage 1.40.2 on branch main

[github-actions]

Update roadie-backstage-plugins workspace at commit RoadieHQ/roadie-backstage-plugins@794d6da for backstage 1.40.2 on branch main.

This PR was created automatically.

⚠️ Manual re-approval required
An override exists at workspaces/roadie-backstage-plugins/backstage.json. This upgrade is a Best-Effort match.
Since the previous version was manually verified to work against the target Backstage version, please review and test again before merging.
The overridden backstage.json has been removed because it's out-of-sync (1.42.5) with the Backstage version of the new source commit (1.40.2).
A new one should be added after testing the plugins against the target Backstage version.
Don't forget to also update the repo-backstage-version field in source.json accordingly.

Click on the following link to see the source diff it introduces: RoadieHQ/roadie-backstage-plugins@c9f6296...794d6da.

Before merging, you need to export the workspace dynamic plugins as OCI images,
and if possible test them inside a RHDH instance.

To do so, you can use the /publish instruction in a PR review comment.
This will start a PR check workflow to:

• export the workspace plugins as dynamic plugins,
• publish them as OCI images
• push the oci-images in the GitHub container registry with a PR-specific tag.