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

Comienza con la guía de troubleshooting enlazada y la salida de estado de CNPG reportada para la versión del plugin 0.9.0. Comprueba el fallo de basebackup y la configuración retentionPolicy de BarmanStore frente al error de recovery-window reportado en CloudNativePG v1.27.1; la tarea estará completada cuando se identifique una causa reproducible o se documente el detalle de configuración o compatibilidad que falta.

Escrito por el modelo de indexación a partir del texto del issue.