Playground package uploader script should support a flag to override existing versions

Was an issue where wrong build were published for 1.9.0 release of the playground packages. To fix it you either have to go and delete every 1.9.0 entry in the storage account(error prone and tedious) or we could just have a flag to override if the file already exists which right now it by design ignore to not republish if the version was already published.

Would be good to also then connect the publish pipeline to be able to set this flag