Steps to replicate the issue (include links if applicable):

sgimeno@deployment-mwmaint03:~$ mwscript extensions/CommunityConfiguration/maintenance/migrateConfig.php --wiki=enwiki CommunityUpdates
Failed to update the store with new config.

== Error details ==
<ul>
<li>
DRAFT: Array value found, but an object is required. Key: GEHomepageCommunityUpdatesThumbnailFile
</li>
<li>
DRAFT: Array value found, but an object is required. Key: GEHomepageCommunityUpdatesCallToAction
</li>
</ul>

What happens?:

The script fails to migrate the schema to the new version. It yields a validation error. The types for both GEHomepageCommunityUpdatesThumbnailFile and GEHomepageCommunityUpdatesCallToAction is object but the version converter sets them as PHP arrays.

What should have happened instead?:

The migration should be applied correctly, creating objects for both keys.

Software version (on Special:Version page; skip for WMF-hosted wikis like Wikipedia):
Beta

Other information (browser name/version, screenshots, etc.):
The script did not yield any error when using dry-run flag, maybe the blob update should be validated in that mode as well.