backup fails despite plugins are available

i got the plugin showing up. facing two errors even after referring the [troubleshooting](https://cloudnative-pg.io/plugin-barman-cloud/docs/troubleshooting/) guide.

found two issues:
1) continous backup status is `OK` . tried basebackup and got requested plugin is not available: [barman-cloud.cloudnative-pg.io](http://barman-cloud.cloudnative-pg.io/) error. plugin status show as below on cnpg status for the cluster.

Name Version Status Reported Operator Capabilities
---- ------- ------ ------------------------------
barman-cloud.cloudnative-pg.io 0.9.0 N/A Reconciler Hooks, Lifecycle Service

2) adding retentionPolicy on barmanstore Yaml and tried to rid off `No recovery window information found in ObjectStore 'db-backupstore' for server 'fusdb'` error. it does not make a difference.

cloudnative PG v1.27.1

Start with the linked troubleshooting guide and the reported CNPG status output for plugin version 0.9.0. Check the basebackup failure and the BarmanStore retentionPolicy configuration against the reported recovery-window error on CloudNativePG v1.27.1; done means identifying a reproducible cause or documenting the missing configuration or compatibility detail.

Rédigé par le modèle d'indexation à partir du texte de l'issue.