ci: dont version private packages (#10333)

## Description
Recently, the `getting-started` jobs in CI have been failing, as seen in this run: 
https://github.com/Agoric/agoric-sdk/actions/runs/11489549535/job/31978567100
https://github.com/Agoric/agoric-sdk/actions/runs/11493429719/job/31989112054?pr=10323


The issue is due to a missing `CHANGELOG.md` file in the `packages/fast-usdc` folder. During the CI process, the script `scripts/registry.sh` runs the following command in the `publish` function:

```bash
yarn lerna version --concurrency 1 prerelease --exact --preid=dev --no-push --no-git-tag-version --yes
```

This command uses `Lerna` to version the packages, a part of which involves updating the `CHANGELOG.md` files for each package. Since the `CHANGELOG.md` file is missing in the `fast-usdc` package, Lerna creates one. This results in a dirty Git tree(There is a check for that), causing subsequent steps in the workflow to fail and leading to the CI job failure.


This PR has been created to add an `--no-private` to avoid versioning private packages. Thanks to @mujahidkay for this suggestion. 

### Security Considerations


### Scaling Considerations


### Documentation Considerations


### Testing Considerations


### Upgrade Considerations

scripts/registry.sh

@@ -73,7 +73,8 @@ publish() {
     # Publish the packages to our local service.
     # without concurrency until https://github.com/Agoric/agoric-sdk/issues/8091
     yarn lerna version --concurrency 1 prerelease --exact \
-      --preid=dev --no-push --no-git-tag-version --yes
+      --preid=dev --no-push --no-git-tag-version --yes \
+      --no-private
 
     # Change any version prefices to an exact match, and merge our versions.
     VERSIONSHASH=$(jq --slurpfile versions <(popd > /dev/null && git cat-file blob "$VERSIONSHASH") \