Release-Please support for "silent" components.

Release-please is taking commits for a [module](https://github.com/googleapis/java-cloud-bom/blob/main/release-please-config.json#L16) configured with **"skip-github-release" : true** and opening a release PR based on it.
We included this module in the config so that we get required updates in its pom file, but do not want to include it in the release PR. Is there another configuration to achieve this result? Or is it a bug? or is it designed to work in this manner?
Opened release [PR](https://github.com/googleapis/java-cloud-bom/pull/5163).