fix(opensearch-dashboards): Generate the SBOM from the built distribution

[dervoeti]

Description

Follow-up to #1630 and #1635. Those fixed the ecosystem over-detection (--type js) and the vector feature set, which removed many components from the OpenSearch Dashboards SBOM, but the npm part was unchanged. The image SBOM still reported dev dependencies like Cypress or Selenium WebDriver, which are not part of the image.

cdxgen ran in the patched source worktree, which is a full development install. The resulting SBOM was the union of every dependencies and devDependencies of the root project and all 15 plugin repositories.
It now runs against the built distribution in /stackable/opensearch-dashboards, which contains exactly what is shipped.

This makes cdxgen walk the installed node_modules instead of the lockfiles, which also closes the license gap (an installed package.json records a license while a Yarn 1 lockfile does not).

Verified by building 3.4.0 locally and running the image SBOM steps from our CI pipeline.

Definition of Done Checklist

Note

Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant.

Please make sure all these things are done and tick the boxes

• Changes are OpenShift compatible
• All added packages (via microdnf or otherwise) have a comment on why they are added
• Things not downloaded from Red Hat repositories should be mirrored in the Stackable repository and downloaded from there
• All packages should have (if available) signatures/hashes verified
• Add an entry to the CHANGELOG.md file
• Integration tests ran successfully

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

boil build <IMAGE> --image-version <RELEASE_VERSION> --strip-architecture --load
kind load docker-image <MANIFEST_URI> --name=<name-of-your-test-cluster>

See the output of boil to retrieve the image manifest URI for <MANIFEST_URI>.